Hummer
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IT DON’T GO BANG-FIRES, HANGFIRES, MISFIRES AND SHORT ORDER COOKS
In looking over the various information I can find on the internet about why it doesn’t go bang there is almost virtually no information on this area for the average shooter to obtain the knowledge needed to investigate these problems and possibly correct the causes.
While with the Army Small Cal Lab and at Aberdeen Proving Ground as Test Director Small Arms and Ammunition I was trained by some of the finest minds in the business.
This ranged from Primer Engineers that did nothing but play with primers, mixes etc their entire careers to Weapons and Ammunition testing at APG. What these folks taught me about small arms ignition reliability and why they might or might not go bang was in its own way amazing to learn as chances are I would have never learned it anywhere else.
It must be understood I grew up on the range so to speak. My Father was a shooter. I went to Camp Perry in l957 for first time and started loading ammo the same year. By the time I finished high school I had gone through over 25,000 primers. Like eveyone else that shoots lots of ammo and has shot all his life and read all that could be found I felt I had a pretty good basis of what goes on in the gun business. I was extremely lucky in that I had a great friend by the name of L.F. Moore (wrote many articles for the shooter over his years) and he was chairman of the Configuration Control Board at Rock Island Arsenal (RIA). He made the recommendation to the Army Small Cal Weapons Lab that I be brought on board.
Upon arrival at the Army Small Cal. Lab I learned in the first week that 20 years of competitive experience was fun but did absolutely nothing to furthur my education in the weapons field. When I went the the Small Cal Lab I was forturnate to make friends with another bachelor who at that time had been in the Ordnance field for 28 years and this guy was an absolute walking computer of the knowledge he could bring up at the mere mention of the subject. He talked incessantly and I listened intently. We talked Ordnance from the time we got in the car for the 37mile drive to work. All day and work and on the way back to the big house we shared in Milford, Pa. At night we loaded and on the weekends went to the range. I worked side by side with him for over a year and then got asked to come to the Special Projects Group working on the Dover Devil Machinegun. Then I was asked to drive down to Aberdeen PG to pick up some dust for a dust test we needed to conduct as weapons were jamming in the desert.
While at Aberdeen I met a guy that had also been brought into the Ordnance Field by L.F. Moore who showed me around and got me loaded with bags of the test dust I was sent to pick up. He then conducted me to the Branch Chief’s officer and I had the shortest job interview in history. I was offered a job as Small Arms and Ammunition Test Director at the Proving Ground. This was the icing on the cake so to speak. I had advanced from being a avid shooter to the Product Engineering section and then to the design section and now I was going to be at the other end of the spectrum and conduct the testing.
At Aberdeen our unnoffical slogan was, “You make’em, we break’em.” And we did.
Depending on the test being conducted we maybe fired one hundred rounds in a day to 10,000 rounds in a day. I calculated one day we burned up $63,000.00 worth of ammunition and was broke down four hours. We also did malfunction investigation of every description and had to document everything. To a shooter a weapon will jam and that is that.
At Aberdeen jammed weapons are broken down into sub catagories. For instance you can have failure to feed, bolt over base, failure to strip, failure to chamber, failure to close, failure to lock, failure to fire, failure to open, failure to extract,failure to eject etc. Testing stopped at each incident and a full written documentation of exactly what occurred was written up. We experienced very few misfires in testing. If memory serves me correctly we had four misfires in 244,000 rounds on the M16A2 test and that caused quite a stir. Hours and hours were spent on trying to determine the causes and every lead was traced until confirmed or disproved. Here I learned that my friend L.F. Moore had actually written much of the Test Operating Procedures that we still used at Aberdeen long after he had moved on to RIA. But back to It Don’t Go Bang.
I have actually observed as many as 50+ misfires in circa 1200 rounds of proof firing 200 guns at another major firearms vendor plant. I got them to let me have the ammo and sent it off for subsequent investigation by my primer engineer friends with measuring microscopes and the other associated specialty tools for examining misfires and they concluded there was nothing wrong with the primers. These guns went to a law enforcement agency and the primer engineers sent a letter sent to that agency identifying there was nothing wrong with the ammo and the person in charge of their ordnance area accepted those guns for issue to the field! ! ! ! Why? Because that individual was good friends with the factory rep of that company who arranged for nice donations of guns as prizes for marksmanship competitions held yearly.
As indicated in past at the Proving Ground, I witnessed many very interesting things, and while I cannot speak for what is done now but when I was there, misfires were given special examination in an effort to determine the causes. I see no reason why it would have changed.
Most everyone has experienced a misfire and a small percentage have experienced a hang fire. (That is when you hear the click, followed by the bang.) Basically to give the reader some idea of exactly what is expected of US ammunition, the government, Winchester, Remington and I assume Federal and CCI all have an allowable misfire rate of one in a million assuming the primers were properly loaded, stored (not exposed to heat, cold, moisture, oil etc) In reality the ignition rate is much better than this but I guess one in a million was a good round number to start at. One manufacturer told me ten years ago in the previous year of inhouse QA testing they had experienced five misfires in 15, 500, 000 rounds that was not attributable to the ignition mechanics or one in three million plus rounds.
Primers need two things for reliable ignition. They need to be hit hard and and they need to be hit at very high speed. Primers are tested in a drop fixture. They are placed in a primer holding fixture and a steel ball is released to have a unretarded free fall before striking the fixture. If memory serves me correctly the testing on these is done with a 2 ounce steel ball dropped from a height of 20 inches which will give 20 inch ounces of energy when it arrives at the fixture.
As well a 20 ounce steel ball dropped from a height of 2 inches will give the same amount of energy upon arriving at the fixture. So what is the difference? After all forty inch ounces is forty inch ounces, well not exactly. Only problem is you will not obtain ignition on the second scenario as the 20 ounce ball has not gained enough velocity prior to striking the mechanism and did not obtain enough velocity to initiate ignition. Thus the statement is they have to be hit fast and hard. One without the other is useless.
In the industry they endeavor to establish the All Fire Drop Height. That is the lowest height the ball can be dropped and obtain 100% ignition reliability. In testing primers they will reduce the height the ball is released an inch at a time until they achieve what is termed the All No Fire Drop Height. Then they will replace the primer recepticle with a “copper” recepticle. Most shooters have read a reference to “CUP” or Copper Units of Pressure. It is a copper cylinder made to very exhaustive standards.
In this instance they are also used in what is referred to as Copper Holders. You have the one used in the fixture and then there are those that are made for each specific caliber. I am blessed with owning a holder for 5.56, 308 and 30.06. Last one I had made cost over $150.00. You may have seen one at a gun show or something and did not know what you were looking at and the guy in all probability did not know what he had either. You are looking for a item that looks exactly like a headspace gage but has a flat bottomed hole in the bottom (where you would look for a primer in a loaded round) about 3/8” deep.
Generally there will be a smaller hole, say .075” drilled all the way through. This is to push the copper back out (from the front) for bench inspection gage testing. There may be writing on it saying what it is and there may not be. You kind of just have to know from experience or in other words there is no writing on a hammer but you know it is by the looks.
The copper is placed so as to receive the energy departed by the striker nose and the ball is dropped at the same height they experienced the all no fire condition. They may take 3 to ten samples. After removing the coppers they are placed on the anvil of a bench inspection gage rigged with a sharp pointed contact (that will find the bottom of the indent without touching the sides.) They record the indents in thousandths of a inch and average the indents. My notes made during that time indicate the All No Fire Indent (ON COPPER) is .007” Where the All Fire Drop Height will exhibit .012” indent (ON COPPER).
The government requirement for the l903, M1, M14 rifle is .020” indent on a copper. A quick comparison shows a substantial difference between the .012” All Fire Indent and the .020” requirement on a weapon system. Or think of it this way. There is nothing but air resistance to retard the 2 ounce steel ball falling however when you wrap a striker with a spring or attempt to drive a striker down a tunnel (inside of a bolt) all kinds of undesirable things can happen to retard the speed at which the striker is delivered to the primer.
There is fairly common knowledge that grit build up in the striker channel of a bolt rifle may retard striker velocity/energy. Friction of the spring rubbing along the striker can cause problems as well. A close examination of the inside of a striker spring may reveal flat spots where the striker rubs against the spring as it is seared up followed by sear disengagement. The travel distance is quite small but still the wear is apparent.
As well if you or a previous owner has ever experienced a blanked primer (this is where the primer appears natural except the area where you would expect an indent is now gone leaving a clean cut hole there) and the blanked out material is nowhere to be found could be a sign to check everything out. There is good liklihood it has traveled up inside the striker opening and will in all probability wind up embedded (so to speak) on the rough inner surface of the striker channel where it is pounded into the body of the bolt. The inside of a bolt is rough (generally) as it is a drilled cavity. Once it is attached to the striker channel it acts in the same manner as a disc brake and may instigate all kinds of problems, i.e. hangfires, misfires, vertical dispersions etc It pays to keep the striker channel clean and closely examined to eliminate build up of foreign materials/conditions that will retard striker velocity.
As well in military weapon systems are subjected for conditions the average hunting rifle will never see such as complete submersion in mud, water, dust environments where the dust is the same consistency as baking flower. Something that hunting rifles are subjected to is extreme cold and or lubrication problems relating to striker energy. Obviously this material will work its way into the striker channel and serve the same funcion – retard striker energy/velocity.
In a cold weather hunting situation springs tend to lose some energy. This coupled with the wrong lubricant being in place on the striker/spring assembly the speed will be severely retarded. Many a rifle has been sold because a guy took it hunting on a cold morning, got a shot at a prize buck and CLICK, nothing happens. I remember I had a friend at Picatinny Arsenal who worked in the machineshop area. He came to me one day and said he had a Browning Lever Action rifle he had purchased from his brother in law for a hundred bucks because it would not fire when he was out hunting. I told him to bring it in for a looksee and he did. He brought in what appeared to be a brand new rifle. In the warmth of the building it sounded like there was sufficient striker action for reliable ignition.
We simply tore it down and took it down to the plating shop and put the action assembly down in the vapor degreaser and took the factory grease out of the striker and action in general and from that day on it shot fine in cold weather. I don’t think the new owner ever told his brother in law why it It Did Not Go Bang.
One thing that needs to be remembered here is the factory folks that make the guns we buy are not necessarily the sharpest folks on the planet. Just because “the factory did it” doesn’t necessarily make it right. As of late I would tend to think if “the factory did it” it is suspect for having a problem or three. And for sure the employees are by and large folks that just need a job and by no reason should they be considered descendents of John M. Browning, Sam Colt, John Garand, Peter and Paul Mauser, or graduates of a certified gunsmithing school or even graduates of high school.
Moreover most don’t even know what they are making and or what it does in the final scheme of things.
So the weapon engineers in the government came up with the minimum requirement of having our rifle small arms deliver .020” copper energy to overcome the elements and conditions the weapon will see in the field. A safety margin to insure reliability in other words. This is basically true except the M16 family of weapons wherein the requirement is .022” copper indent. There is only one harder small arms primer to ignite than the 5.56MM round, that is the Cal. 50 BMG primer.
A little background on the M16 family of weapons. As initially developed the M16 striker had a rather large head making the striker much heavier than it is today. In those early days standard small rifle primers were being loaded in the 5.56MM and when the troops dropped the carriers home the striker being free it its run was free to continue forward and strike the primer. With the cup being normal dimensions, the striker heavy there were enough tic offs (as they were named) to cause a Product Improvement Program (PIP) to be conducted to correct the problem. At least two changes were made to eliminate this condition. One the head of the striker was reduced to what it is today by removing much of the weight and the primer cup for the 5.56MM was made heavier (thicker) to enable it to sustain the inertia hits. The inertia phenomena is not restricted to the M16. It is evident of the M1 Garand and the M14 rifle however they did not exhibit the tic off condition as the striker was much lighter.
I constantly read about accidental discharges dropping the bolt carrier home on the AR rifles. This condition can remedied by the use of RemingtonBR Primers and or the CCI Mil Spec Small Rifle Primer. These are heavier (thicker) and thus designed for the AR series of rifles. Perhaps other vendors primer cups are heavier to meet the mil spec for the 5.56MM NATO but I am not aware of them.
I have read of some excuses of supposed accidental firings where the M16 “fell over” was “dropped” or some other story and someone was shot as a result. I personally do not accept these explanations as I personally conducted the drop test on the M16A2 Rifle when I was the Test Director on this weapon system for the Marine Corps in l982/3 time frame at Aberdeen. Bullets were pulled and propellant dumped and the rifles were purposely dropped on a steel test bed cast into cement at Aberdeen. I dropped and dropped and dropped. Nothing. I held the rifle with the muzzle seven feet in the air and dropped it on the muzzle. No fire. Finally I climbed up on a steel building and dropped it from 10 feet in the air. No fire. Finally I got it to fire. I literally used it as if it were a speer and threw it from the roof of the building to impact on the steel test bed muzzle down. It only ignited once in three tries if I remember correctly and the muzzle was point at right angles to the planet.
The flash suppressor on this rifle was severely distorted to the point it need replacing. So the bottom line here is I don’t buy this “I dropped my M16 and it went off” theory. Sounds feasible but not likely barring an Act of God. Now if they have ammunition with primers in them that do not meet the milspec, the bolt is locked in the open position with a charged magazine inserted and then it is knocked over causing the bolt to be released…. well maybe. I would like to see it proved with repeatability. If the round is already placed in the chamber, no magazine in place and the bolt dropped, now you have a different program as the bolt encounters no resistance as it travels into battery. With a charged magazine in place bolt velocity is retarded due to the energy required to strip the round from the magazine.
For general interest purposes I also have conducted striker indent on copper tests on other rifles.
I have two Model 98 Mausers made many years ago. Both are of the South American contracts series. One was a 8MM that I rebarreled to 308 and a 30.06 variation rebarreled to 30.06.
One delivers .022” copper, the other .024 indent after 50 years compression ! ! ! ! ! A Ml911 Swiss carbine rebarreled to 308 still delivers .022” indent after 75 years compression! ! ! ! ! These things have energy up the yeng yang. Now for those of you that think US production is at the cutting edge of reliability, consider the following: Two years ago Santa Clause secretly delivered to me three new rifles made by three different firms. At that point things started to go South. I did bench mark testing and evaluation prior to initial firing and one gave .015” indent and closed on a NO-GO gage. The other brand gave .017 indent. The third gave .015” indent. I wrote letters to the Chief Engineers of all three firms. All three firms told me to send them in.
One of the three firms Product Service Managers emailed me and wanted me to participate in a conference call with him and their Chief Engineer about the problem with their particular weapon. This was very interesting. During the call they told me they had no idea of what the striker energy was on their rifles and that they had run out of testing material years ago and did not do any more testing. They also indicated that SAAMI had just dropped their recommendation of copper energy to .016” and they weren’t even meeting that.
I was not happy with learning this in that only leaves a small excess energy available to insure ignition reliability in adverse conditions.
The second vendor replaced the barrel and action with a new one and put a used bolt in it with so much wear the finish was gone and the knob rusted. I rechecked copper energy and it was lower than what I had sent them. Back it went. Next time gun came back it was all new but they had changed the stock to a plastic trigger guard and it was broken in the box.
The third firm replaced the striker spring and sent me three coppers all indicating .022” indent which I measured and got the same readings on and then conducted my own test and got .022” on mine.
Or look at it this way. You are going after Kodiak Bear in cold weather with a 300 Win Mag. Rifle you just purchased. With the above in mind, wouldn’t this just give you lots of good warm feelings of what may happen when you irritate one of these and he/she decides your time has come. Talk about a bad time to get a click instead of a boom, you are in prime condition to wind up on the bear’s den wall. Considerng the guy that assembled your rifle may have been a short order cook in Jersey last month just exudes confidence doesn’t it?
If the above doesn’t give you a sick feeling in your stomach then the following is really going to get your undivided attention. Yes folks the above is the good news, stand by for the rest of the story.
We are supposed to be shooting center fire rifles correct? Well what exactly is the definition of a center fire insofar as the firearms industry is concerned? Folks this is really going to be an attention getter.
We have all seen and looked at the indents left in primers of center fire rifles. Most are off center just a little right? In the government small arms field we called them Eccentric Firing Pin Impacts. Frankford Arsenal (FA) did an exhaustive work on this many years ago and authored a magnificent document entitled Effects of Eccentric Firing Pin Impacts on Primer Sensitivity. This study utilized several different calibers, 30 Carbine, Cal. 30, 45 ACP and 50 BMG.
Fixtures were fabricated to deliver striker impacts .020” and .040” offcenter of the primer.
Considering that most center fire rifles have striker nose diameters of circa .060” it basically offset the impact of the striker by one third the diameter and two thirds.
Remember earlier I stated the industry seems to prefer one half or .030” offset based on a .060” diameter striker nose.
Drop testing was also conducted on 7.62MM cases at .004” .023”, 039” and .049” off center hits. The results showed the sensitivity of the primers decreased as the blow of the striker became more eccentric. Translated this means the furthur you hit off center the harder the primer must be struck to insure reliable ignition ! ! ! ! ! ! ! ! Now we know from above there is a definent tendency for the striker spring to take a set and lose energy so if you are off center at the start, things can only go downhill from there.
The above testing was conducted with a four ounce ball delivering 64 inch ounces of energy. Or in other words they really hit them hard! ! ! !
Now consider this scenario. This testing was done with a free falling ball and was not hindered by any foreign material to retard the striker velocity as described above. Couple this with decreased striker energy and increased eccentric impacts the primer sensitivity will deteriorate and the misfire rate will vastly accelerate.
Why are these offsets encountered. Several reasons for these offsets come to mind. For instance the base dimension on a 308 Winchester case of commercial manufacturer is .465-6” on new cases. Consider a factory chamber might be reamed at .470-471” in the same area; there is offset potential right there as the extractor/ejector will force the base of the case all the way to one side in the chamber. Next consider those cases you have seen that really exhibit a swell at the base. I have seen them at .473” (on a fired case) which is way over recommended max but then again who is watching the store. The short order cook may have transferred to final inspection at the vendor’s plant.
I knew one guy (now deceased) who said they all got togeher in his department and put in a pool every day to bribe the inspector to cull certain configurations in wood and not send it to the stock shop as wood with certain characteristics was much harder to work and slowed the production which meant they made less money that day. So if they got easier wood to work they made more money and the guy cutting the wood made more money and eveyone was happy. Any want to bet this hasn’t happened in other areas besides the stock shop?
I have a friend who used to work at Springfield Armory (SA). When the Armory closed many of the people that worked to government standards for many years did not transfer and stayed in the New England area and went to work for other gun companies. He went back to the area to retrieve some stuff he had in storage and made a visit to some of his old SA friends he had worked with and they were complaining about what happened at the company picnic that year. This must have been l979/80 time frame as I remember when he returned he told me the main complaint these former government workers had to their new management at the picnic/meeting was the Quality of the stuff going out the door was terrible. Management’s reply was so what, we are still making 30% net or the short order cook just moved up to management or book keeping and these people being human are interested in MONEY.
As well on certain designs the ability to drill the bolt way hole (in the receiver)and hold dead center on that datum line is quite difficult. Not to mention the long narrow hole drilled into the bolt itself. Awful deep hole to drill without it wandering. Or say the bolt way is off .010” and he striker channel is off .010 and he chamber on a 30 cal case is circa .473 diameter that is about .025” off set right there! ! ! ! Attached there will be a picture of three primers. The left primer example (which looks really good) was looked at with a 7X glass and dial calipers measured the center of the actual indent to the outside of the primer indicated this indent is off center .027”
Next the threads must be put in. I have seen much evidence that threads are not correctly cut at right angles to the bore center line. A friend who actually was very knowledgable about guns worked for Remington. He told me to always look at a bunch of new rifles where the barrel contacts the front of the receiver and if you can see where the barrel appears to be jammed up tight on one side and not so tight on the other side leave it laying. This is because the threads are not straight. Next you have he problem of the bore may be off center in the barrel stock. This is quite common. If sufficent care is not taken to insure the bore is centered and turned on centers and that the outside of the barrel is cleaned up prior to threading there will be furthur offset to one side and a floating reamer holder is going to follow the hole just as if it were a pilot hole which theoretically it is! You have to keep in mind they are having to turn out hundreds of rifles per day and they get paid piece rate. They have a politically correct term for this, called, “being on incentive”.
I was having trouble getting a barrel off a Remington 700 once. Called my friend and he said heat the receiver with a torch as that was one that was so loose they coated the threads with plumbers pipe dope to keep it from coming loose. Sure enough after heating the receiver it screwed out very easily and had gray pipe dope all over the threads. I have seen variations of thread diameters in the range of .010” which is bound to affect several areas.
To prove this pull up Dave Manson Precision Reamers and look at his website. He makes a kit that does a nice job of realigning the factory threads and squaring everything up. Gunsmiths have coined a nice term for this, Blueprinting the action, translated it means to make it like it should have been before leaving the factory. I have a friend who I watched use one of these on a 700 Magnum action. After the threads were recut there was a marked difference in fired cases from factory and what the Manson reamers did. The Manson outfit brought the striker indent much closer to dead center.
Primer Storage: All the directions say to keep them in a “cool dry place”. Per one primer engineer I know who was a shooter is gets a bit more serious than that. As a result of his furthur instructions/recommendations I will pass these on to you as to what I do. I buy primers by the case of 5000 and try to get them right out of the factory. As soon as I get them they go into a 20MM ammo can (which will hold four or five cases of primers).
As I need primers I will go and quickly open the 20MM can and remove 1000 and close the can as soon as possible. These 1000 go into a 30 cal ammo can until used. I only open this can in the lowest humidity conditions possible. Winter or a air conditioned area in the summer. I remove 100 or 200 primers and place these in a plastic bag with a closure type arrangement. I remove the primers, seat them, charge the cases, seat the bullets in as short a time span as is practical. He even recommends if you are going to be hunting etc coat the ends with clear nail polish wiping off the excess on a paper towel will leave the polish in place around the circumference of the seated primer. He then places these in plastic boxes and they go back into another GI ammo can for storage until he goes to the range.
Humidity is the worst enemy followed by lubricant contamination. I am aware of one lot of government 308 Match ammo that malfunction investigation showed had oil contamination from a over lubricated machine on the loading line. Another lot was discarded when it was found to have oil in the primer mix that dropped in from a mixer blending the ingredients.
In the government when misfires occur with a ammunition lot or anything else out of the ordinary a Quality Deficiency Report (QDR) is supposed to be filled out and sent to Picatinny Arsenal for Malfunction investigation. I was told by my Branch Chief that the first thing done is to querry the world wide ammo control point as to how much of that ammo lot remains in the system. When the report comes back that there is say three hundred to four hundred thousand of that lot they follow this with a World Wide Destruct Advisory to destroy all ammunition of that lot number remaining in any depot. Regardless of whether it is bad or not. It is cheaper to destroy that to investigate! ! !
You may have noted that with the exception of match ammo, you have never seen government ammo newer than three years old being used. This is because all the new ammo goes into War Reserves in the ammo storage depots around the world and the oldest ammo is then removed and sent to the troops which is generally three years for some calibers and maybe forty years for others. Remember we went all through WW2, Korea and Viet Nam with WW2 50 cal ammunition because so much had been warehoused. Not to worry here folks, government ammo stored in their original unopened cans has a MINIMUM expected life of 125 years. The trick is to never open the can until time to use it. Once opened and exposed to the air the shelf life drops remarkably fast.
One last word on striker springs. I have seen bolts removed and torn down and found the striker spring in pieces. I saw one broken in three pieces. Also before you get to misfires and hang fires you may notice elevation problems. Remember All Fire was .012 and All No Fire was .007? Well at .009” copper indent the primer engineers say you will experience problems and I have seen new unfired commercial guns within the last 18 months delivered that exhibit .014”/.015” copper indent. Chances are if you have printed this out the paper it is printed on is .003 to .004 thick. Put two pieces together in your fingers and you will have a feel for just how slim the margin is between “All Fire and All No Fire.”! ! ! !
OK that isn’t SAAMI approved but remember folks SAAMI is only a coordinating activity for the industry. They do no QA inspection at vendor plants and as management has reportedly said, “So what we are still making 30% net.” Seems to say it all doesn’t it.
In looking over the various information I can find on the internet about why it doesn’t go bang there is almost virtually no information on this area for the average shooter to obtain the knowledge needed to investigate these problems and possibly correct the causes.
While with the Army Small Cal Lab and at Aberdeen Proving Ground as Test Director Small Arms and Ammunition I was trained by some of the finest minds in the business.
This ranged from Primer Engineers that did nothing but play with primers, mixes etc their entire careers to Weapons and Ammunition testing at APG. What these folks taught me about small arms ignition reliability and why they might or might not go bang was in its own way amazing to learn as chances are I would have never learned it anywhere else.
It must be understood I grew up on the range so to speak. My Father was a shooter. I went to Camp Perry in l957 for first time and started loading ammo the same year. By the time I finished high school I had gone through over 25,000 primers. Like eveyone else that shoots lots of ammo and has shot all his life and read all that could be found I felt I had a pretty good basis of what goes on in the gun business. I was extremely lucky in that I had a great friend by the name of L.F. Moore (wrote many articles for the shooter over his years) and he was chairman of the Configuration Control Board at Rock Island Arsenal (RIA). He made the recommendation to the Army Small Cal Weapons Lab that I be brought on board.
Upon arrival at the Army Small Cal. Lab I learned in the first week that 20 years of competitive experience was fun but did absolutely nothing to furthur my education in the weapons field. When I went the the Small Cal Lab I was forturnate to make friends with another bachelor who at that time had been in the Ordnance field for 28 years and this guy was an absolute walking computer of the knowledge he could bring up at the mere mention of the subject. He talked incessantly and I listened intently. We talked Ordnance from the time we got in the car for the 37mile drive to work. All day and work and on the way back to the big house we shared in Milford, Pa. At night we loaded and on the weekends went to the range. I worked side by side with him for over a year and then got asked to come to the Special Projects Group working on the Dover Devil Machinegun. Then I was asked to drive down to Aberdeen PG to pick up some dust for a dust test we needed to conduct as weapons were jamming in the desert.
While at Aberdeen I met a guy that had also been brought into the Ordnance Field by L.F. Moore who showed me around and got me loaded with bags of the test dust I was sent to pick up. He then conducted me to the Branch Chief’s officer and I had the shortest job interview in history. I was offered a job as Small Arms and Ammunition Test Director at the Proving Ground. This was the icing on the cake so to speak. I had advanced from being a avid shooter to the Product Engineering section and then to the design section and now I was going to be at the other end of the spectrum and conduct the testing.
At Aberdeen our unnoffical slogan was, “You make’em, we break’em.” And we did.
Depending on the test being conducted we maybe fired one hundred rounds in a day to 10,000 rounds in a day. I calculated one day we burned up $63,000.00 worth of ammunition and was broke down four hours. We also did malfunction investigation of every description and had to document everything. To a shooter a weapon will jam and that is that.
At Aberdeen jammed weapons are broken down into sub catagories. For instance you can have failure to feed, bolt over base, failure to strip, failure to chamber, failure to close, failure to lock, failure to fire, failure to open, failure to extract,failure to eject etc. Testing stopped at each incident and a full written documentation of exactly what occurred was written up. We experienced very few misfires in testing. If memory serves me correctly we had four misfires in 244,000 rounds on the M16A2 test and that caused quite a stir. Hours and hours were spent on trying to determine the causes and every lead was traced until confirmed or disproved. Here I learned that my friend L.F. Moore had actually written much of the Test Operating Procedures that we still used at Aberdeen long after he had moved on to RIA. But back to It Don’t Go Bang.
I have actually observed as many as 50+ misfires in circa 1200 rounds of proof firing 200 guns at another major firearms vendor plant. I got them to let me have the ammo and sent it off for subsequent investigation by my primer engineer friends with measuring microscopes and the other associated specialty tools for examining misfires and they concluded there was nothing wrong with the primers. These guns went to a law enforcement agency and the primer engineers sent a letter sent to that agency identifying there was nothing wrong with the ammo and the person in charge of their ordnance area accepted those guns for issue to the field! ! ! ! Why? Because that individual was good friends with the factory rep of that company who arranged for nice donations of guns as prizes for marksmanship competitions held yearly.
As indicated in past at the Proving Ground, I witnessed many very interesting things, and while I cannot speak for what is done now but when I was there, misfires were given special examination in an effort to determine the causes. I see no reason why it would have changed.
Most everyone has experienced a misfire and a small percentage have experienced a hang fire. (That is when you hear the click, followed by the bang.) Basically to give the reader some idea of exactly what is expected of US ammunition, the government, Winchester, Remington and I assume Federal and CCI all have an allowable misfire rate of one in a million assuming the primers were properly loaded, stored (not exposed to heat, cold, moisture, oil etc) In reality the ignition rate is much better than this but I guess one in a million was a good round number to start at. One manufacturer told me ten years ago in the previous year of inhouse QA testing they had experienced five misfires in 15, 500, 000 rounds that was not attributable to the ignition mechanics or one in three million plus rounds.
Primers need two things for reliable ignition. They need to be hit hard and and they need to be hit at very high speed. Primers are tested in a drop fixture. They are placed in a primer holding fixture and a steel ball is released to have a unretarded free fall before striking the fixture. If memory serves me correctly the testing on these is done with a 2 ounce steel ball dropped from a height of 20 inches which will give 20 inch ounces of energy when it arrives at the fixture.
As well a 20 ounce steel ball dropped from a height of 2 inches will give the same amount of energy upon arriving at the fixture. So what is the difference? After all forty inch ounces is forty inch ounces, well not exactly. Only problem is you will not obtain ignition on the second scenario as the 20 ounce ball has not gained enough velocity prior to striking the mechanism and did not obtain enough velocity to initiate ignition. Thus the statement is they have to be hit fast and hard. One without the other is useless.
In the industry they endeavor to establish the All Fire Drop Height. That is the lowest height the ball can be dropped and obtain 100% ignition reliability. In testing primers they will reduce the height the ball is released an inch at a time until they achieve what is termed the All No Fire Drop Height. Then they will replace the primer recepticle with a “copper” recepticle. Most shooters have read a reference to “CUP” or Copper Units of Pressure. It is a copper cylinder made to very exhaustive standards.
In this instance they are also used in what is referred to as Copper Holders. You have the one used in the fixture and then there are those that are made for each specific caliber. I am blessed with owning a holder for 5.56, 308 and 30.06. Last one I had made cost over $150.00. You may have seen one at a gun show or something and did not know what you were looking at and the guy in all probability did not know what he had either. You are looking for a item that looks exactly like a headspace gage but has a flat bottomed hole in the bottom (where you would look for a primer in a loaded round) about 3/8” deep.
Generally there will be a smaller hole, say .075” drilled all the way through. This is to push the copper back out (from the front) for bench inspection gage testing. There may be writing on it saying what it is and there may not be. You kind of just have to know from experience or in other words there is no writing on a hammer but you know it is by the looks.
The copper is placed so as to receive the energy departed by the striker nose and the ball is dropped at the same height they experienced the all no fire condition. They may take 3 to ten samples. After removing the coppers they are placed on the anvil of a bench inspection gage rigged with a sharp pointed contact (that will find the bottom of the indent without touching the sides.) They record the indents in thousandths of a inch and average the indents. My notes made during that time indicate the All No Fire Indent (ON COPPER) is .007” Where the All Fire Drop Height will exhibit .012” indent (ON COPPER).
The government requirement for the l903, M1, M14 rifle is .020” indent on a copper. A quick comparison shows a substantial difference between the .012” All Fire Indent and the .020” requirement on a weapon system. Or think of it this way. There is nothing but air resistance to retard the 2 ounce steel ball falling however when you wrap a striker with a spring or attempt to drive a striker down a tunnel (inside of a bolt) all kinds of undesirable things can happen to retard the speed at which the striker is delivered to the primer.
There is fairly common knowledge that grit build up in the striker channel of a bolt rifle may retard striker velocity/energy. Friction of the spring rubbing along the striker can cause problems as well. A close examination of the inside of a striker spring may reveal flat spots where the striker rubs against the spring as it is seared up followed by sear disengagement. The travel distance is quite small but still the wear is apparent.
As well if you or a previous owner has ever experienced a blanked primer (this is where the primer appears natural except the area where you would expect an indent is now gone leaving a clean cut hole there) and the blanked out material is nowhere to be found could be a sign to check everything out. There is good liklihood it has traveled up inside the striker opening and will in all probability wind up embedded (so to speak) on the rough inner surface of the striker channel where it is pounded into the body of the bolt. The inside of a bolt is rough (generally) as it is a drilled cavity. Once it is attached to the striker channel it acts in the same manner as a disc brake and may instigate all kinds of problems, i.e. hangfires, misfires, vertical dispersions etc It pays to keep the striker channel clean and closely examined to eliminate build up of foreign materials/conditions that will retard striker velocity.
As well in military weapon systems are subjected for conditions the average hunting rifle will never see such as complete submersion in mud, water, dust environments where the dust is the same consistency as baking flower. Something that hunting rifles are subjected to is extreme cold and or lubrication problems relating to striker energy. Obviously this material will work its way into the striker channel and serve the same funcion – retard striker energy/velocity.
In a cold weather hunting situation springs tend to lose some energy. This coupled with the wrong lubricant being in place on the striker/spring assembly the speed will be severely retarded. Many a rifle has been sold because a guy took it hunting on a cold morning, got a shot at a prize buck and CLICK, nothing happens. I remember I had a friend at Picatinny Arsenal who worked in the machineshop area. He came to me one day and said he had a Browning Lever Action rifle he had purchased from his brother in law for a hundred bucks because it would not fire when he was out hunting. I told him to bring it in for a looksee and he did. He brought in what appeared to be a brand new rifle. In the warmth of the building it sounded like there was sufficient striker action for reliable ignition.
We simply tore it down and took it down to the plating shop and put the action assembly down in the vapor degreaser and took the factory grease out of the striker and action in general and from that day on it shot fine in cold weather. I don’t think the new owner ever told his brother in law why it It Did Not Go Bang.
One thing that needs to be remembered here is the factory folks that make the guns we buy are not necessarily the sharpest folks on the planet. Just because “the factory did it” doesn’t necessarily make it right. As of late I would tend to think if “the factory did it” it is suspect for having a problem or three. And for sure the employees are by and large folks that just need a job and by no reason should they be considered descendents of John M. Browning, Sam Colt, John Garand, Peter and Paul Mauser, or graduates of a certified gunsmithing school or even graduates of high school.
Moreover most don’t even know what they are making and or what it does in the final scheme of things.
So the weapon engineers in the government came up with the minimum requirement of having our rifle small arms deliver .020” copper energy to overcome the elements and conditions the weapon will see in the field. A safety margin to insure reliability in other words. This is basically true except the M16 family of weapons wherein the requirement is .022” copper indent. There is only one harder small arms primer to ignite than the 5.56MM round, that is the Cal. 50 BMG primer.
A little background on the M16 family of weapons. As initially developed the M16 striker had a rather large head making the striker much heavier than it is today. In those early days standard small rifle primers were being loaded in the 5.56MM and when the troops dropped the carriers home the striker being free it its run was free to continue forward and strike the primer. With the cup being normal dimensions, the striker heavy there were enough tic offs (as they were named) to cause a Product Improvement Program (PIP) to be conducted to correct the problem. At least two changes were made to eliminate this condition. One the head of the striker was reduced to what it is today by removing much of the weight and the primer cup for the 5.56MM was made heavier (thicker) to enable it to sustain the inertia hits. The inertia phenomena is not restricted to the M16. It is evident of the M1 Garand and the M14 rifle however they did not exhibit the tic off condition as the striker was much lighter.
I constantly read about accidental discharges dropping the bolt carrier home on the AR rifles. This condition can remedied by the use of RemingtonBR Primers and or the CCI Mil Spec Small Rifle Primer. These are heavier (thicker) and thus designed for the AR series of rifles. Perhaps other vendors primer cups are heavier to meet the mil spec for the 5.56MM NATO but I am not aware of them.
I have read of some excuses of supposed accidental firings where the M16 “fell over” was “dropped” or some other story and someone was shot as a result. I personally do not accept these explanations as I personally conducted the drop test on the M16A2 Rifle when I was the Test Director on this weapon system for the Marine Corps in l982/3 time frame at Aberdeen. Bullets were pulled and propellant dumped and the rifles were purposely dropped on a steel test bed cast into cement at Aberdeen. I dropped and dropped and dropped. Nothing. I held the rifle with the muzzle seven feet in the air and dropped it on the muzzle. No fire. Finally I climbed up on a steel building and dropped it from 10 feet in the air. No fire. Finally I got it to fire. I literally used it as if it were a speer and threw it from the roof of the building to impact on the steel test bed muzzle down. It only ignited once in three tries if I remember correctly and the muzzle was point at right angles to the planet.
The flash suppressor on this rifle was severely distorted to the point it need replacing. So the bottom line here is I don’t buy this “I dropped my M16 and it went off” theory. Sounds feasible but not likely barring an Act of God. Now if they have ammunition with primers in them that do not meet the milspec, the bolt is locked in the open position with a charged magazine inserted and then it is knocked over causing the bolt to be released…. well maybe. I would like to see it proved with repeatability. If the round is already placed in the chamber, no magazine in place and the bolt dropped, now you have a different program as the bolt encounters no resistance as it travels into battery. With a charged magazine in place bolt velocity is retarded due to the energy required to strip the round from the magazine.
For general interest purposes I also have conducted striker indent on copper tests on other rifles.
I have two Model 98 Mausers made many years ago. Both are of the South American contracts series. One was a 8MM that I rebarreled to 308 and a 30.06 variation rebarreled to 30.06.
One delivers .022” copper, the other .024 indent after 50 years compression ! ! ! ! ! A Ml911 Swiss carbine rebarreled to 308 still delivers .022” indent after 75 years compression! ! ! ! ! These things have energy up the yeng yang. Now for those of you that think US production is at the cutting edge of reliability, consider the following: Two years ago Santa Clause secretly delivered to me three new rifles made by three different firms. At that point things started to go South. I did bench mark testing and evaluation prior to initial firing and one gave .015” indent and closed on a NO-GO gage. The other brand gave .017 indent. The third gave .015” indent. I wrote letters to the Chief Engineers of all three firms. All three firms told me to send them in.
One of the three firms Product Service Managers emailed me and wanted me to participate in a conference call with him and their Chief Engineer about the problem with their particular weapon. This was very interesting. During the call they told me they had no idea of what the striker energy was on their rifles and that they had run out of testing material years ago and did not do any more testing. They also indicated that SAAMI had just dropped their recommendation of copper energy to .016” and they weren’t even meeting that.
I was not happy with learning this in that only leaves a small excess energy available to insure ignition reliability in adverse conditions.
The second vendor replaced the barrel and action with a new one and put a used bolt in it with so much wear the finish was gone and the knob rusted. I rechecked copper energy and it was lower than what I had sent them. Back it went. Next time gun came back it was all new but they had changed the stock to a plastic trigger guard and it was broken in the box.
The third firm replaced the striker spring and sent me three coppers all indicating .022” indent which I measured and got the same readings on and then conducted my own test and got .022” on mine.
Or look at it this way. You are going after Kodiak Bear in cold weather with a 300 Win Mag. Rifle you just purchased. With the above in mind, wouldn’t this just give you lots of good warm feelings of what may happen when you irritate one of these and he/she decides your time has come. Talk about a bad time to get a click instead of a boom, you are in prime condition to wind up on the bear’s den wall. Considerng the guy that assembled your rifle may have been a short order cook in Jersey last month just exudes confidence doesn’t it?
If the above doesn’t give you a sick feeling in your stomach then the following is really going to get your undivided attention. Yes folks the above is the good news, stand by for the rest of the story.
We are supposed to be shooting center fire rifles correct? Well what exactly is the definition of a center fire insofar as the firearms industry is concerned? Folks this is really going to be an attention getter.
We have all seen and looked at the indents left in primers of center fire rifles. Most are off center just a little right? In the government small arms field we called them Eccentric Firing Pin Impacts. Frankford Arsenal (FA) did an exhaustive work on this many years ago and authored a magnificent document entitled Effects of Eccentric Firing Pin Impacts on Primer Sensitivity. This study utilized several different calibers, 30 Carbine, Cal. 30, 45 ACP and 50 BMG.
Fixtures were fabricated to deliver striker impacts .020” and .040” offcenter of the primer.
Considering that most center fire rifles have striker nose diameters of circa .060” it basically offset the impact of the striker by one third the diameter and two thirds.
Remember earlier I stated the industry seems to prefer one half or .030” offset based on a .060” diameter striker nose.
Drop testing was also conducted on 7.62MM cases at .004” .023”, 039” and .049” off center hits. The results showed the sensitivity of the primers decreased as the blow of the striker became more eccentric. Translated this means the furthur you hit off center the harder the primer must be struck to insure reliable ignition ! ! ! ! ! ! ! ! Now we know from above there is a definent tendency for the striker spring to take a set and lose energy so if you are off center at the start, things can only go downhill from there.
The above testing was conducted with a four ounce ball delivering 64 inch ounces of energy. Or in other words they really hit them hard! ! ! !
Now consider this scenario. This testing was done with a free falling ball and was not hindered by any foreign material to retard the striker velocity as described above. Couple this with decreased striker energy and increased eccentric impacts the primer sensitivity will deteriorate and the misfire rate will vastly accelerate.
Why are these offsets encountered. Several reasons for these offsets come to mind. For instance the base dimension on a 308 Winchester case of commercial manufacturer is .465-6” on new cases. Consider a factory chamber might be reamed at .470-471” in the same area; there is offset potential right there as the extractor/ejector will force the base of the case all the way to one side in the chamber. Next consider those cases you have seen that really exhibit a swell at the base. I have seen them at .473” (on a fired case) which is way over recommended max but then again who is watching the store. The short order cook may have transferred to final inspection at the vendor’s plant.
I knew one guy (now deceased) who said they all got togeher in his department and put in a pool every day to bribe the inspector to cull certain configurations in wood and not send it to the stock shop as wood with certain characteristics was much harder to work and slowed the production which meant they made less money that day. So if they got easier wood to work they made more money and the guy cutting the wood made more money and eveyone was happy. Any want to bet this hasn’t happened in other areas besides the stock shop?
I have a friend who used to work at Springfield Armory (SA). When the Armory closed many of the people that worked to government standards for many years did not transfer and stayed in the New England area and went to work for other gun companies. He went back to the area to retrieve some stuff he had in storage and made a visit to some of his old SA friends he had worked with and they were complaining about what happened at the company picnic that year. This must have been l979/80 time frame as I remember when he returned he told me the main complaint these former government workers had to their new management at the picnic/meeting was the Quality of the stuff going out the door was terrible. Management’s reply was so what, we are still making 30% net or the short order cook just moved up to management or book keeping and these people being human are interested in MONEY.
As well on certain designs the ability to drill the bolt way hole (in the receiver)and hold dead center on that datum line is quite difficult. Not to mention the long narrow hole drilled into the bolt itself. Awful deep hole to drill without it wandering. Or say the bolt way is off .010” and he striker channel is off .010 and he chamber on a 30 cal case is circa .473 diameter that is about .025” off set right there! ! ! ! Attached there will be a picture of three primers. The left primer example (which looks really good) was looked at with a 7X glass and dial calipers measured the center of the actual indent to the outside of the primer indicated this indent is off center .027”
Next the threads must be put in. I have seen much evidence that threads are not correctly cut at right angles to the bore center line. A friend who actually was very knowledgable about guns worked for Remington. He told me to always look at a bunch of new rifles where the barrel contacts the front of the receiver and if you can see where the barrel appears to be jammed up tight on one side and not so tight on the other side leave it laying. This is because the threads are not straight. Next you have he problem of the bore may be off center in the barrel stock. This is quite common. If sufficent care is not taken to insure the bore is centered and turned on centers and that the outside of the barrel is cleaned up prior to threading there will be furthur offset to one side and a floating reamer holder is going to follow the hole just as if it were a pilot hole which theoretically it is! You have to keep in mind they are having to turn out hundreds of rifles per day and they get paid piece rate. They have a politically correct term for this, called, “being on incentive”.
I was having trouble getting a barrel off a Remington 700 once. Called my friend and he said heat the receiver with a torch as that was one that was so loose they coated the threads with plumbers pipe dope to keep it from coming loose. Sure enough after heating the receiver it screwed out very easily and had gray pipe dope all over the threads. I have seen variations of thread diameters in the range of .010” which is bound to affect several areas.
To prove this pull up Dave Manson Precision Reamers and look at his website. He makes a kit that does a nice job of realigning the factory threads and squaring everything up. Gunsmiths have coined a nice term for this, Blueprinting the action, translated it means to make it like it should have been before leaving the factory. I have a friend who I watched use one of these on a 700 Magnum action. After the threads were recut there was a marked difference in fired cases from factory and what the Manson reamers did. The Manson outfit brought the striker indent much closer to dead center.
Primer Storage: All the directions say to keep them in a “cool dry place”. Per one primer engineer I know who was a shooter is gets a bit more serious than that. As a result of his furthur instructions/recommendations I will pass these on to you as to what I do. I buy primers by the case of 5000 and try to get them right out of the factory. As soon as I get them they go into a 20MM ammo can (which will hold four or five cases of primers).
As I need primers I will go and quickly open the 20MM can and remove 1000 and close the can as soon as possible. These 1000 go into a 30 cal ammo can until used. I only open this can in the lowest humidity conditions possible. Winter or a air conditioned area in the summer. I remove 100 or 200 primers and place these in a plastic bag with a closure type arrangement. I remove the primers, seat them, charge the cases, seat the bullets in as short a time span as is practical. He even recommends if you are going to be hunting etc coat the ends with clear nail polish wiping off the excess on a paper towel will leave the polish in place around the circumference of the seated primer. He then places these in plastic boxes and they go back into another GI ammo can for storage until he goes to the range.
Humidity is the worst enemy followed by lubricant contamination. I am aware of one lot of government 308 Match ammo that malfunction investigation showed had oil contamination from a over lubricated machine on the loading line. Another lot was discarded when it was found to have oil in the primer mix that dropped in from a mixer blending the ingredients.
In the government when misfires occur with a ammunition lot or anything else out of the ordinary a Quality Deficiency Report (QDR) is supposed to be filled out and sent to Picatinny Arsenal for Malfunction investigation. I was told by my Branch Chief that the first thing done is to querry the world wide ammo control point as to how much of that ammo lot remains in the system. When the report comes back that there is say three hundred to four hundred thousand of that lot they follow this with a World Wide Destruct Advisory to destroy all ammunition of that lot number remaining in any depot. Regardless of whether it is bad or not. It is cheaper to destroy that to investigate! ! !
You may have noted that with the exception of match ammo, you have never seen government ammo newer than three years old being used. This is because all the new ammo goes into War Reserves in the ammo storage depots around the world and the oldest ammo is then removed and sent to the troops which is generally three years for some calibers and maybe forty years for others. Remember we went all through WW2, Korea and Viet Nam with WW2 50 cal ammunition because so much had been warehoused. Not to worry here folks, government ammo stored in their original unopened cans has a MINIMUM expected life of 125 years. The trick is to never open the can until time to use it. Once opened and exposed to the air the shelf life drops remarkably fast.
One last word on striker springs. I have seen bolts removed and torn down and found the striker spring in pieces. I saw one broken in three pieces. Also before you get to misfires and hang fires you may notice elevation problems. Remember All Fire was .012 and All No Fire was .007? Well at .009” copper indent the primer engineers say you will experience problems and I have seen new unfired commercial guns within the last 18 months delivered that exhibit .014”/.015” copper indent. Chances are if you have printed this out the paper it is printed on is .003 to .004 thick. Put two pieces together in your fingers and you will have a feel for just how slim the margin is between “All Fire and All No Fire.”! ! ! !
OK that isn’t SAAMI approved but remember folks SAAMI is only a coordinating activity for the industry. They do no QA inspection at vendor plants and as management has reportedly said, “So what we are still making 30% net.” Seems to say it all doesn’t it.
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