Double Rifle Load Development Shooting Distance

[Hunt101]

Hi, I've got a new .500 double that I'm having a hard time getting a load that doesn't cross. I've owned other doubles in the past up to .470, and I've never had such a hard time getting a double rifle to uncross. Before I make the assumption its a regulation issue I want to rule out the possibility I'm shooting the gun poorly.

I've been shooting the rifle from sticks at 50 yards, this has been my standard practice for all my doubles. I'm shooting this rifle with open sights.

This brings me to my next set of questions, during load development does anyone shoot at 25 yards?

In the event a rifle is cross firing, has anyone ever set up targets in a line to establish at what rate they are crossing? Example, setting a target at 25 yards and then one in line at 50 yards, fire into the 25 yard target and then review how the barrels printed on the 50 yard target.

I'm thinking this would prove out shooter error concerning a crossed point of impact at 50 yards, if the 25 yard target showed right on right and left on left, however the 50 yard target showed a crossed point of impact.

Just to answer the obvious question in advance:
1. I've fired the ammo in which the rifle was regulated with and it crosses, and did so for another shooter I shoot doubles with.

 

[rookhawk]

Ken Owen in Moscow, TN.

He is who needs to see this rifle. He will figure out if it's regulation, or load development at issue.

 

[Hunt101]

I've had the pleasure of working with Ken once before, but my understanding is that he is no longer doing this type of work. Does anyone know for sure if he is or isn't?

 

[rookhawk]

Typically 50-60 yards is where testing is done. Maybe it doesn't matter?

Shoot a group of four shots , two and two, left right, at 100 yards.

If they are pear shape and inside a dinner plate or better, do you care when/if they cross? You just want them to run effectively parallel for the effective shooting range of the rifle.

If it won't do this, then you can adjust velocity of your loads. If still a problem, you need Ken Owen.

 

[rookhawk]

I've had the pleasure of working with Ken once before, but my understanding is that he is no longer doing this type of work. Does anyone know for sure if he is or isn't?

He is retired. He comes out of retirement for very polite people that say please a lot. He returns to retirement as soon as he is slightly annoyed by some ill placed words or any sign of discord. No one is faster, cheaper, more qualified.

I suspect you'll have success with Ken taking your job.

 

[Hunt101]

Thank You for the advice, I'll dig through my emails and see if I still have his contact info. I completely get what your saying regarding overall group size and relative shooting distance, I think more than anything it bothers me if the rifle is indeed crossing. While shooting today I was getting groups of 3" at 50 yards, but based on my spotter the right barrel was on the left side of the target and left on the right. I then moved my target up to 25 yards and the rifle put them both damn near in the same hole. Bad thing about this 500 is I can only take about 20 rounds per shooting session, well I did 30 one time, but that was pretty rough.

 

[rookhawk]

Almost all double rifles cross, it's a rare bird that flies parallel to infinity. Usually, they cross at 60 yards or at least that was the regulators intent.

If you're saying they are crossing at 25 yards, that's not so great. If they stay in a small pattern at 100 yards, then you don't care anyway.

If you want to tinker before seeking Ken, you could try to drop the load a grain or two and see if that keeps them from crossing so soon.

Disclaimer: I don't know crap about doubles. I've owned them. I've had these problems with a 500, a 350, and a 9.3. Whatever sense I'm making is only because I'm parroting back what Ken has told me.

 

[Ray B]

I have no personal experience with double rifles, but I recall the issue being that on firing the rifle is torqued to the side. So prior to firing the barrel is pointed inboard, then as the bullet moves through the barrel, the barrel moves to the side. Getting the barrel to be pointed at the bullseye as the bullet leaves it would be the issue. So if the bullets are crossing at too close a distance, it seems to me that the solution would be to increase barrel time so that the barrel would have torqued a little more prior to the bullet leaving. If this is so, I would try a slight increase in bullet weight and see if that helps the situation.

 

[rookhawk]

@Ray B usually a 500NE has a 570 bullet. Few options to move bullet up or down marginally. Next size is 500gr and not nearly as good in many ways.

So velocity via powder change is usually how you change convergence

 

[Hunt101]

Most of my loads to this point have been with RL15, and all with 570 grain bullets, the 570 grain bullets seem to be the most readily available. I have tried traditional solids and some of the monolithic solids as well, I'm experiencing crossing results with all. I'm trying to systematically go through the process to make sure I'm not corrupting my data, which brings me back to the proposed option of shooting at a 25 yard target with a 5o yard target placed behind and inline with the 25 yard target. I guess I just want to prove out shooter error in the crossing results seen at 5o yards, and prevent jumping around in load data if the 50 yard results were shooter error.

Has anyone ever heard of a good method to confirm crossing results are not shooter related?

 

[rookhawk]

Shoot at 100 yards and see if they all land on paper. If one barrel lands shots on paper and the other are all misses, you have a lot of divergence and thus, a regulation problem.

 

[PHOENIX PHIL]

Most of my loads to this point have been with RL15

Hunt101, what I know about doubles is that they have two barrels, if both are loaded, you can make the rifle go bang twice without any other mechanical motion short of a second trigger squeeze. So I don't have a lot to offer you.

But over the past several years I have done a fair amount of load development including with RL15. I can say RL15 is one powder I tend to avoid. It's not because you can't get a good load with it, because I have particuarly in my son's .308. The reason I don't care for it is that it's known to have a fair amount of variation from lot to lot. I ran into this a few years back and had to redevelop a load. And I'm not talking about moving a tenth or two away from the original load, it was more than that. A little more research confirmed other shooters experienced the same. I even know of some people who really like the powder who will buy a lot of it and then pour out all their canisters into a big bowl and mix it up effectively homogenizing the various lots that they came from. I prefer the simpler route of just buying Varget it's virtual ballistic twin.

My point in all of this along with @rookhawk's comments is I wouldn't be surprised at all if you need to redevelop / re-regulate your load and don't be surprised at how far "off" you are from the original load.

It would also seem in this case you're supposed to slow the bullets down a bit. So if it were me I think I'd work up loads starting at where you are now and then drop in 0.5gr increments until you reach a load 2-3gr below your starting point. At that point I'd shoot each and carefully watch what the spread is doing. To make it interesting, I think I'd put up targets at 25 and 50 yards in line with each other.

 

[PaulT]

Phil is on the mark regarding his comments on R 15.

I am one of those who "blended" it in order to "stabilize" the variation.
Several years back I bought 15lbs of R 15, emptied it all in a big tub and mixed it thoroughly, then poured it back in the individual containers.
Since doing that I found it very well suited for the loads that I was using in my V.C .500

If you are interested in using 475gn C.E.B Raptors you can p.m me and I can give you the range of loads for R 15 that was known to regulate amongst more than half a dozen .500 cal doubles of several different makes.

 

[PaulT]

Have replied to your pm and email.
Please see your email as we have the ball rolling.

Lets get this sorted well before your hunt for some peace of mind.

Regards.

Paul.

 

[Bos Javanicus]

Might pay to just go back to the beginning, you will need to confirm 100% that your shots are crossing first. Also you mentioned you were using shooting sticks? Don't rest the rifle in the V of the sticks, place your hand in the V and the rifle in your hand. I use two separate targets when doing load development, one for the left barrel and one for the right barrel. And overlay them after to get my group size. Of course you can do what ever you like. How fast are your loads going? A chronograph is more than handy in load development and will take a lot of the guess work out of what you are doing. I won't do load development without one. What you want to do is match the regulated velocity using very similar projectiles to what it was regulated for. Now as you use a .500 I would recommend a bit of a blast shield to avoid getting false velocity readings from the muzzle blast when you use your chronograph.
Now, were your shots shooting high or low, or at point of aim?
Most, (and I use that term loosely) double rifles will shoot both barrels low and to the opposite side if velocity is too fast i.e. Crossing and low. As velocity is decreased the shots should rise on the target and get to your point of aim. If you decrease your loads too much your shots will spread again. Slow loads should print left barrel left and high and right barrel right and high.
Doubles as I'm sure you know can be a bit fiddly to work up a regulated load, even primers can make a difference, Federal 215 are the go. And what shoots well in one rifle will not necessarily shoot well in another. Try some H4350 and start low at around 103gns for a .500NE and work your way up to about 106gns and see how you go.

 

[Bos Javanicus]

There is a book out. Shooting the British double rifle by Graeme Wright. It has all the above info plus much much more. I found it essential reading for both loading and shooting. Don't worry about the title, it caters for all doubles.

 

[Hunt101]

Might pay to just go back to the beginning, you will need to confirm 100% that your shots are crossing first. Also you mentioned you were using shooting sticks? Don't rest the rifle in the V of the sticks, place your hand in the V and the rifle in your hand. I use two separate targets when doing load development, one for the left barrel and one for the right barrel. And overlay them after to get my group size. Of course you can do what ever you like. How fast are your loads going? A chronograph is more than handy in load development and will take a lot of the guess work out of what you are doing. I won't do load development without one. What you want to do is match the regulated velocity using very similar projectiles to what it was regulated for. Now as you use a .500 I would recommend a bit of a blast shield to avoid getting false velocity readings from the muzzle blast when you use your chronograph.
Now, were your shots shooting high or low, or at point of aim?
Most, (and I use that term loosely) double rifles will shoot both barrels low and to the opposite side if velocity is too fast i.e. Crossing and low. As velocity is decreased the shots should rise on the target and get to your point of aim. If you decrease your loads too much your shots will spread again. Slow loads should print left barrel left and high and right barrel right and high.
Doubles as I'm sure you know can be a bit fiddly to work up a regulated load, even primers can make a difference, Federal 215 are the go. And what shoots well in one rifle will not necessarily shoot well in another. Try some H4350 and start low at around 103gns for a .500NE and work your way up to about 106gns and see how you go.

When shooting from sticks I always have my hand in contact with the sticks not the rifle, meaning the back of my left hand is the only thing resting on the V of the sticks. Typically if I'm shooting at the same paper, I'll use a buddy to spot the impacts, when testing alone I've been doing exactly as you suggested two separate targets. I've been as slow as mid 1700s and as high as 2175 in velocity, I'm in the dark however as to what the regulating speed was for the rifle, I've requested the information but was told the maker doesn't record it.

If interested I have all my shots recorded in an excel that show Powder, Charge, Shooting style Sticks vs Bench, Bullet, Velocity, Point of Impact, and few other things to try and help me sort the data. Sorting the data has become a challenge, I believe the following based on what I've shot and recorded.

My rifle likes Hornady Solids @ 1800 ft per sec., as velocity increases towards 2050 the impacts moves up and seem to cross more. Currently I'm seeing the best results out of H4831, and I do have some promising results from 114 grains getting the 570 grain bullet to about 1950.

I plan to test some more this week with H4831 & RL15, currently I'm doing all my testing from a bench (No rear bag, just front bag with the back of my left hand on the front bag for support) and after about 16 rounds I'm done. Here lies the biggest problem for me and a tight timeline, I can only take so much from the .500 before I have to call it quits, and from a bench its worse. This leads me to follow more of the dirty barrel testing format as opposed to cleaning before each outing, having to foul the barrels each outing would cut my 16 rounds down significantly.

I'm shooting from the bench currently to get the most consistent data, and then will move away from the bench and back to sticks.

 

[Bos Javanicus]

Looks like you are going about it the right way, and have spent a fair bit of time trying to sort it. I shoot a .500 NE too so know where you are coming from there. About 16 or so rounds in a short session does me in too.
3" and crossing at 50 may not be the end of the world, what does it group like at 75 yards? I'm happy to put two shots into a 10" circle at 75 yards off hand and I don't care if they cross if they stay in that circle.

 

[rookhawk]

Looks like you are going about it the right way, and have spent a fair bit of time trying to sort it. I shoot a .500 NE too so know where you are coming from there. About 16 or so rounds in a short session does me in too.
3" and crossing at 50 may not be the end of the world, what does it group like at 75 yards? I'm happy to put two shots into a 10" circle at 75 yards off hand and I don't care if they cross if they stay in that circle.

Exactly the reasoning of my advice. If he can put all of them on paper off sticks at 100 yards I couldn't care less if they crossed and when.

Knowing where they cross is somewhat worthless trivia. It is trivia you discover while getting a load to regulate the sights but it isn't a goal of the process, just something learned by the process.

How big a group, four shots, two from each barrel, are you making at 50 and 100 yards shooting off sticks?

 

[Rolf_T]

A suggestion is to use one of these when shooting at the range: https://www.primos.com/products/trigger-sticks/two-point-gun-rest/
Helps on the aiming/hitting part and since you shoot standing also increases your endurance with those large caliber cigars...