Are there pressure signs here?

[Pheroze]

Hey guys I am wondering if you would mind weighing in on this load development.

I am trying to load CEB Maximus 150gr for my 308 Norma Mag. CEB does not have data but from other reloading manuals I expected 3250 fps max.

I am experimenting with using the ladder method - I loaded .3gr from a starting load based on other 150gr bullets in a manual. I have 23 loaded cartridges up to a listed max load for Woodleighs. I am only half way up, at #13, and I am exceeding the max. Also, I can't discern a plateau so I am a little stuck. What I have noticed are three distinct groups on my target but all bullets landed very close. I can now see a ring on the fired brass but the primer looks pretty standard.

I am thinking #10 is what I should try a 3 shot group with next time. That is 74.2gr RL-19. But, am I short changing myself and should I keep climbing the ladder?

Sorry for the long post. I tried to group the pictures identifying the #

The crazy SD is because I recorded all shots in on list.

The bolt is not hard to lift.

Any ideas would be appreciated. To be honest, I think any would work because the bullet just seems to be very accurate regardless of load.

 

[Pheroze]

The target at 100 yards

 

[BourbonTrail]

Looks like a little bit of pressure. How greasy is your chamber? Also how does your bolt face look?


Sent from my iPhone using New Forum mobile app

 

[Pheroze]

Chamber isn't greasy at all I don't think.

Here is the bolt face.

 

[Hunter4752001]

To me the primers look like you're got high pressures. There's what appears to be cratering and flow back around the firing pin strike. I can't make out the 'ring' you're describing but if its there, it may be the early signs of brass being over stretched leading eventually to case head separation.

An issue with various monometal designs is that lead core load data doesn't necessarily apply. The CEB design in particular features an over size ring to maximize bullet seal.

Good luck with your project, but if it were me I'd back off a bit. I'd rather use a load that was slower than optimal rather than a load that was borderline on pressure.

 

[IdaRam]

Pheroze, what are you using for primers? Gold makes me think maybe Remington?
Your primers are not really that flattened. If you are not experiencing any “sticky” bolt lift or difficulty extracting I would be more inclined to say the cratering you are seeing on the primer may be more related to the firing pin hole in the bolt face / firing pin tip. Do you have some other reloads with a jacketed bullet that are within book charge weight? How do those look? Hard to tell from the pic of your bolt face, but that hole doesn’t look very round to me. The more gap or chamfer around that firing pin hole, the more you will see that cratering look.
I would load up a “medium pressure” standard lead and copper bullet load from a loading manual with that same primer and see if you see the same thing. And if possible I would try other primers. Preferably CCI 250 Large Rifle Magnum, and see what they look like.
And I would do something like that before you move on to the hotter loads in your ladder.
That said, I’m not convinced you’ve got pressure issues yet.

 

[Pheroze]

Pheroze, what are you using for primers? Gold makes me think maybe Remington?
Your primers are not really that flattened. If you are not experiencing any “sticky” bolt lift or difficulty extracting I would be more inclined to say the cratering you are seeing on the primer may be more related to the firing pin hole in the bolt face / firing pin tip. Do you have some other reloads with a jacketed bullet that are within book charge weight? How do those look? Hard to tell from the pic of your bolt face, but that hole doesn’t look very round to me. The more gap or chamfer around that firing pin hole, the more you will see that cratering look.
I would load up a “medium pressure” standard lead and copper bullet load from a loading manual with that same primer and see if you see the same thing. And if possible I would try other primers. Preferably CCI 250 Large Rifle Magnum, and see what they look like.
And I would do something like that before you move on to the hotter loads in your ladder.
That said, I’m not convinced you’ve got pressure issues yet.

The priner is Winchester Large Magnum rifle. This photo is a Swift A Frame load of 70.5gr H4831 2868fps

I think there is always a bit of cratering with my rifle.

I used a template for a graph and this is what I saw (the template in excel is a weight watchers graph so it says "goal weight" rather than speed lol) I am thinking #9 that is expanded is maybe the better place to work from?

Here is the brass for #9

 

[sestoppelman]

I tend to agree with IdaRam. If you recall other loads cratering as well, I think its probably normal for that rifle. Primers are not flat. No hard bolt lift.
As to any ring its hard to see here, but if you have any doubts, do the bent wire probe and see if you can feel any depression on the inside of the case starting at bottom going up to about a half inch. If you feel the probe catching, thats a sign of "gonna come apart soon".
That has little to nothing to do with your loads however and is a function of your die setting, probably pushing the shoulder down more than necessary.

 

[bruce moulds]

pheroze,
if your primer pockets prove to be tight when you reload the cases, then the problem of peak pressure is not an issue case wise.
should primers be loose after about 3 reloads the load is too hot.
however you still have a cratering issue which would be fixed by having a competent gunsmith bushing the firing pin hole and modifying the firing pin in some way if necessary.
the rifle certainly seems to want to shoot.
also what ses said.
bruce.

 

[Hogpatrol]

Borescope it and check for a carbon ring.

 

[Mekaniks]

I don't remember which action you are using, but I think I would double check the firing pin and make sure its adjusted properly and has the correct amount of travel.

 

[Pheroze]

Borescope it and check for a carbon ring.

I think it's too new to get that? I cleaned it and seems ok.

I don't remember which action you are using, but I think I would double check the firing pin and make sure its adjusted properly and has the correct amount of travel.

ZKK 600 action. I will ask my gunsmith about the cratering and ask that.

 

[Areaonereal]

No pressure sign...my Rem 700 does the same to primers, can be normal on the way the firing strikes the primer, bushing of the firing pin corrects the cratering in most cases.

 

[One Day...]

I tend to agree.

A slightly oversized firing pin hole (machining tolerance? which would not be all that uncommon on a ZKK...) will cause this, but based on what I see I would tend to quote the famous "don't fix it if it ain't broken" which I think it is not

As long as the bolt opens as easily as on an empty chamber I would not be overly worried

 

[C.W. Richter]

What was the ambient temperature when you were test firing the loads??

 

[One Day...]

Following on my previous post, for example compare this .257 Wby Weatherby factory load (100 g TTSX) fired in a Blaser R8 chamber (left), to your brass (right).

The primer on my brass is considerably more flattened against the bolt head - typically indicating a higher chamber pressure - even though there is no primer reflow ("cratering") through the firing pin hole - likely indicating tighter firing pin hole drilling tolerances.

Observe that the brass also shows a very clear ring. I can actually feel it when I drag my nail across it. This is typically due to hunting rifles chambers being a little loose (even Blasers! ) compared to match rifles, in order to allow field-dirty ammo to load.

I am not concerned in the least with primer flattening and brass ring on my factory ammo in my factory barrel, and based on what you said and showed, Pheroze, I would not be worried in your case. I would paraphrase Franklin D. Roosevelt's 1933 first inaugural address: “the only thing we have to fear is fear itself” and note that sometimes in our pursuit of perfection we can get a bit over-worried. I know that I have been known to

If the load is within reloading books specs (THAT is important), allows an easy bolt lift, shoots the bullet you like accurately, and delivers the ballistics you seek, it seems that you got yourself a winner


PS: as we all know, max load for one bullet typically has no relation with max load for another bullet. What with bullet length, bearing surfaces, jacket or mono material hardness, material flow bands, bore rider profile, etc. etc. etc. But we all know that...

 

[Pheroze]

What was the ambient temperature when you were test firing the loads??

About 26C. It was hot (for a Canadian) in the sun but pleasant in the shade.

Following on my previous post, for example compare this .257 Wby Weatherby factory load (100 g TTSX) fired in a Blaser R8 chamber (left), to your brass (right).

The primer on my brass is considerably more flattened against the bolt head - typically indicating a higher chamber pressure - even though there is no primer reflow ("cratering") through the firing pin hole - likely indicating tighter firing pin hole drilling tolerances.

View attachment 405592 View attachment 405591

Observe that the brass also shows a very clear ring. I can actually feel it when I drag my nail across it. This is typically due to hunting rifles chambers being a little loose (even Blasers! ) compared to match rifles, in order to allow field-dirty ammo to load.

View attachment 405599

I am not concerned in the least with primer flattening and brass ring on my factory ammo in my factory barrel, and based on what you said and showed, Pheroze, I would not be worried in your case. I would paraphrase Franklin D. Roosevelt's 1933 first inaugural address: “the only thing we have to fear is fear itself” and note that sometimes in our pursuit of perfection we can get a bit over-worried. I know that I have been known to

If the load is within reloading books specs (THAT is important), allows an easy bolt lift, shoots the bullet you like accurately, and delivers the ballistics you seek, it seems that you got yourself a winner


PS: as we all know, max load for one bullet typically has no relation with max load for another bullet. What with bullet length, bearing surfaces, jacket or mono material hardness, material flow bands, bore rider profile, etc. etc. etc. But we all know that...

Your illustrations about the primer are very interesting. I am not sure if I will continue with the ladder though because I am not sure I want a bullet going that fast for how I hunt. I want to maximize the use of this design but too much velocity may just cause too much damage. Although, seeing that plateau at the end makes me wonder what cartridge 14 and 15 will do

 

[BourbonTrail]

Reason I asked about “greasy” chamber (what I should have said was “lubricated”. Magnum cartridges like your Norma mag or my 300 Wby will send the case rearward if the chamber isn’t good and dry. That can give a false positive sometimes.

Speaking of pressures: increasing L->R in picture with leftmost being unfired. Note the brass deformation as pressure goes up. Yours doesn’t have this, but it’s a warning sign of “bolt thrust” where the case jumps rearward.

The one on the far right required a mallet to open.

 

[Inline6]

Agree with others, bush the fire pin hole. Not sure with you being on the north side of the border. LRI does really good work and it would be worth your time to make a call to them.

 

[Inline6]

Reason I asked about “greasy” chamber (what I should have said was “lubricated”. Magnum cartridges like your Norma mag or my 300 Wby will send the case rearward if the chamber isn’t good and dry. That can give a false positive sometimes.

Speaking of pressures: increasing L->R in picture with leftmost being unfired. Note the brass deformation as pressure goes up. Yours doesn’t have this, but it’s a warning sign of “bolt thrust” where the case jumps rearward.
View attachment 405600
The one on the far right required a mallet to open.

It appears you have ejector swipe on your first fired round. Probably should have backed down from that load (just an option).