I was shooting my 450/400 3.25 this weekend and have noticed a new to me problem.
Following directions as laid forth by Graeme Wright I have been developing loads for my double. I was going throught the second set of five doubles, cafefully marking L and R bullet placements. I began noticing a stiffening when trying to open the breech after each set. Upon closer inspection I noticed that my primers were cratered. The bevel of the primers was still visible so I do not believe overpressure is the problem. There was also no flattening of the primers or the brass imprinting or stamping.
There is also the problem of a few of the primers backing out of the primer pockets. I believe from past reading that this would be an indication of headspaceing problems or possibly a weakened firing pin spring?
Any other toughts?

I am especially concerned because this load has my L and R shots within 2 inches with a minimum of crosssover at 40 yards. I am also within 4 inches at 100 yards standing freehand. I would hate to have a problem with the rifle as I am approching hunting accuracy.
Any other direction from those more knowledgeable would be greatly appreciated.
Frank

Frank:

What you describe could be the product of a host of problems. Just not enough information here to say.

What..............:

Brand of brass are you using?

Bullet?

Primer?

Propellant? At what charge did the gun
begin to get harder to open? What charge
did you start and stop at. What were the
velocities throughout?

Since these problems seem to have gradually appeared as you were laddering up and the gun was printing with "a minimum of crossover" (you should have stopped when they began to cross), my guess is that you have seriously excessive pressure. The fact that you have cratering and primers backing out isn't good. The lack of flattening and imprinting, in this context, is utterly useless information, as conventional pressure signs don't normally begin to show up until well beyond the maximum service pressure for this cartridge.

Velocity data is crucial here.
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"Serious rifles have two barrels, everything else just burns gunpowder."

I’ve had this problem with a few of my older black powder and early nitro double rifles. What was happening to me as the firing pin’s were of the large diameter type with the accompanying large diameter holes to sleeve them. This allowed the primer to easily flow back into the holes. My solution was one of two things:

For guns that have firing pin sleeve plates, replace with a smaller diameter firing pin and hole. This worked like a charm.

For guns without sleeve plates, use the hardest primer you can find. I think CCI Magnum rifle worked the best for me, but I didn’t try them all and there may be even better ones out there. This helped quite a bit, it didn’t eliminate the problem completely, but it made it acceptable. Just note that the harder primers need a very strong blow to set them off when using the large diameter firing pins.

quote:

Originally posted by 400 Nitro Express:
Frank:


Since these problems seem to have gradually appeared as you were laddering up and the gun was printing with "a minimum of crossover" (You should have stopped when they bean to cross), my guess is that you have seriously excessive pressure. ------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

Frank, these are words to chisel into your loading bench top, right next to your press!

Sure, those and many other issues with the strikers and bushings can cause lots of problems. All of these rifles were built for the much larger diameter Berdan caps and often don't work well with Boxer. However, such problems are usually evident with all loads. This problem seems to have appeared only after the load was increased, so it's probably pressure, not the pins.

The use of hard primers in the full nitros should be carefully avoided.
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"Serious rifles have two barrels, everything else just burns gunpowder."

I have been using the Federal Magnum primers. Loaded using 81 gr. powder which is less than listed by Wright. This load is right at 2000 fps. The cratering showed at 83 gr. but was not much more evident at 85gr.
I am going to load a bunch more at 79 and 80 and see if it goes away.
Frank

If the crossover is under 2 inches should I back off even more?

Given the charge weight, I assume you're using IMR 4831? 85 grains is a lot. Are you using a cronograph? This is the Ozzie, right? Is it 55 Cordite or 60? The Federal 215 is a hot primer and has a fairly soft cup, which is exactly what you want.

Once the barrels begin to cross, there's no point to increasing the charge further, as they will only cross more.

I've used 4831 in the 3 1/4", but never got the consistency with it that RL 15 gives. Yeah, reduce the charge and see if the barrels uncross and the cratering goes away.

If that doesn't work, try RL 15. Start with 64 grains and a couple grains Dacron, and work up a grain at a time. Stop when the barrels come together. Stop when you reach 2150 fps in any case.
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"Serious rifles have two barrels, everything else just burns gunpowder."

Thank you 400. That is what I will do next.
Frank

So I got some RL 15 and started the process. I have resized Full length everything and made sure every piece will drop in on both R and L barrels.
I have primed with the Federal 215's and checked the scales with my check weights. This powder is finer than the 4831 so I can see why two grains of Dacron is necessary. I had been using only .5 grains with the 4831. I am starting with 60 gr. and adding one grain each to 10 rounds. Using the Hawk 35 jacket 400 grain soft. I will be using the Chrono to confirm the velocity as I watch for the accuracy.
This will take a while to shoot while I wait for the barrel to cool between sets.
Yes this is the Charles Osbourne. It is marked 60 cordite- 400 max

Thank you again. I will let you know after the weekend.
Frank

Since the Hawk bullets are softer, Frank, you shouldd be able to achieve the desired velocity with less powder. The Hawks seal better. For my rifle which is a 55 cord 400 Max, I usually use 64 grains of RL-15 with Dacron filler. With the Hawk bullets I can drop down to around 62 grain and it prints where it should.

A word of advice to others working up loads for your doubles, Every round you fire at the range needs to go over a Chronograph. If you don't use one it's just guess work at best.

Frank,
I had similar problems in my 470 with Hawk bullets....I switched to Woodleigh and they went away...I suggest you try a different bullet.

Frank:

Work up with Woodleighs first, then the Hawks. The Hawks will usually require less powder. The Hawk explains the pressure problem. Those charges of IMR 4831 would definitely be way too hot for the Hawk.
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"Serious rifles have two barrels, everything else just burns gunpowder."

Thanks guys. I have some woodleighs on order.
Frank

Frank,
You need some Woodleighs? I have some .408 400 grain Weldcores I can send to you, overnight if need be.

rkmojo@aol.com

Thank you Rusty, that is very generous. I think regular mail will still get them here with time for me to practice. I will purchase them if you would.

PO Box 670
Hydesville, CA
95547

Frank

Frank,
I sent a box of .408 400 grain Woodleigh Weldcores to you via Priority Mail. They should be to your place by Tuesday.

Best regards,

Rusty

quote:

Originally posted by Rusty:
Frank,
I sent a box of .408 400 grain Woodleigh Weldcores to you via Priority Mail. They should be to your place by Tuesday.

Best regards,

Rusty

Thank you very much Rusty. I will make this good for you when we meet in Texas.

I went out today and shot several loads with 'RL15. 63 grains was still around 3 inches apart but no crossover and the primers have no craters or flattening or backing out at all. I am having the triggerpull lightened so I won't have so long to worry it over while trying to shoot off the bench. I also did some two-legged shooting and am keeping things on a pieplate for hunting purposes within the 100 yards or less range.
Rusty, I will let you know when the bullets arrive and will get another chance to go out and shoot before leaving for Cooley.
Frank

Frank,

Having shot a lot of very different loads and calibers, the primer crater is all too typical of excessive pressure.

Go up to a slower powder.

When primers crater on test loads, continuing to shoot the same load will destroy your rifle.

I was involved in pushing mil calibers to the max. When a primer cratered, that was time to either back off on the powder we were using or bump to a slower burner.

FYI

Jim

Thanks Jim. That is exactly what I have done. I went to a different powder and started with 10% lower load than was suggested. RL 15 seems to be a much easier powder to work with and I am getting decent accuracy at 2050 fps average after allowing the barrel to cool between shots. It was around 75 in the sun and that is about as warm as we get here on a regular basis. I don't believe I will go any higher as Dallas is sure to be warmer and if I can keep it on a pie plate I am happy.
Frank

Frank
2050fps is plenty enough to get good performance from woodleigh softs on all game, and on elephant heads with woodleigh solids.

You say your hits are 3 inches apart... At what distance.

It seems like many [all actually] of my "Bolt Rifle Trash" friends, get a double rifle and expect it to shoot like a Sniper Rifle.

A double rifle is a hunting rifle, not a sniper rifle.

I recently bought a Winchester 1895 rifle in 405WCF. In the June 2006 NRA magazine a tested 405 shot 3.75 inch groups at 100 yards.
This is a one bbled rifle. What should you expect from a double rifle 40 cal and up???

In reality, if I can hit both bbls on a nine inch pie plate, every time kneeling from 100 yards, and every time standing from 50 yards
EVERY big game animal in the universe is in mortal danger.

quote:

You say your hits are 3 inches apart... At what distance.

Last week I was shooting at 40 paces. Today I was at 50 paces. No sandbags so I know much of that was me. I have always judged my rifles by how I can shoot them either leaning against a tree or sitting braced against a rock.
I am anxious to see how well it really shoots when others at Coley do some shooting.
Frank

Frank,

RL 15 is the base powder for yor rifle. And it is great powder.

But you need to see what the others have. I have powders you can have with your rounds. Let's do a quarter pound at a time and let's run this through my program, though. Never know when I'll need to create something.





What bullets are you pushing?

Jim,
I think Franks double is an old English Double rifle. In my old double I only use RL-15. RL-15 comes closer to matching the pressure curve of Cordite. As long as you use the Dacron filler to hold it in place, it will provide a safe pressure round for these older doubles and it will give you probably the most consistant velocities you'll ever get in your double. RL-15 is position sensitive.

With modern doubles you can work up just about any load you'd like. Once again remembering that double rifles were designed to use "Low Pressure" rounds.

Frank, I have been working lately on a Jeffery 400 3". I went through all the usual powders, and finally settled on 4064.

68.5 grs 4064, 1.5 grs Dacron filler, Fed 215, Bell Brass and 400gr Woodleigh Soft gave me 2050fps and a 4 shot group of 1 inch at 50 yds from a sitting bench.

R-15 was close but I couldn't get better than 2.5 inches.

Now like NE 450 No 2 says: Time to get off the bench and shoot!

Funny how 4064 doesn't get much press but I find it the best powder by far for my 416 Hoffman and now this 400.

As an interesting note, I also tried NE 450 No2's 75% theory and tried Hornady 300 gr .411 softs with the same 68.5 4064. They regulated nicely at 2125fps and hit to the sights, good Hog and range load.

Good luck with your Osborne.

This is indeed an old English. A Charles Osbourne. I am sorry I have not posted photos but other obligations at the moment.
I started out with 4831 but that was way too much of a load and without the chrono initially it was not really the smart thing to do. I was using Hawk bullets to begin with.
I then tried the rl 15 with the same hawk bullets and yesterdays results were much better. I started with 58 gr. and built up a gr. at a time to the 63 without having any crossover as I had gotten with the 4831. The velocities went from 1875/1920 to 2050 staying relativly on target both R and L.
When I get back out there on Wednesday I will be trying the woodleigh's with the RL 15 and will let you know how that goes.
As long as I don't get craters or primers backing out I will be happy with the 4 inch accuracy for now. I am sure the rifle will do better as well.
Jim, Thanks for the suggestions. I have written them down for my future loads.
Tony is right, I just need to shoot this a bunch.
Frank

I tried IMR 4831 in both .400s years ago, and quickly abandoned it. IMR 4064 will certainly work in the .400s as it is very close to RL 15. I used 68 grains in mine for a time before trying RL 15.

Cordite was a fast burning, double based propellant, and it's often easier to get rifles regulated with it to shoot well with faster burning propellants.

I spoke to a tech guy at one of the big commercial ammo companies last week. They're working up .450/.400 3". They were unable to reach standard velocity within pressure limits with IMR 4831. The CIP max average for the 3" is 40,600 PSI and 82 grains IMR 4831 produced 43000 plus. A charge of 76 grains ran 38000 plus, but velocity was too low. Remember that the standard load for both .400s is the same, but that the 3" operates at lower pressure and velocity because of it's larger case.

Even slight pressure signs in the flanged nitros are scary. The tech guys say that when you start to get pressure signs on primers or a drawn brass case you're north of 60000 PSI. The CIP max for the .450/.400 3 1/4" is 42,700 PSI. Once conventional pressure signs appear, you're beyond proof pressure.
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"Serious rifles have two barrels, everything else just burns gunpowder."

60,000 PSI? Yikes.

I was looking into using Norma's MRP-2 for 470 loads. It is a very slow powder and Norma's published load was something in the 115 grain range.

I wrote to Norma to see if this load was correct, since the balllistics program I ran this through went red on warnings of serious overpressure. They told me that the pressure was over 36,000 PSI.

Based on the warnings from the QuickLoad program, I passed on the MRP-2.

Just picked up from 4831 SC, which sounds promising for 47 loads based on some people's experience here.

I am more cautious with loads for a DR that loads for a bolt action. With my pretty face so close to the breach on a DR, I certainly don't want any mishaps.

Jim,
Do you have QuickLoad?
I'll be glad to run the numbers for MRP-2 for you.

Rusty,

Quick Load is the program I used.

I knew there was a good reason I bought it! LOL!

If you want to see the program go wild, put in 128 grains of MRP-2 with a 500 grain bullet with 24" barrels. 128 Grains was what the published max was, but they suggested in an e-mail that 113 grains would give me 2155 fps.