Opening a small primer pocket to accept the large primer

[barryaclarke]

The .454 uses a small rifle primer and the .460 uses the large rifle primer. I’ve read where some reloaders are trimming down .460 brass to .454 to enable them to load with the large primer. If one wanted to save a few $$$ wouldn’t make sense instead of buying the very expensive .460 brass, you buy .454 brass and open the primer pocket because they are the same except for the length of the brass? I have heard of people opening the small primer pockets on the 45 acp to accept the large primer, but I can't any information on how they did it. I see RCBS has a carbide primer pocket uniformer tool, but I’m guessing this won't cut a small pocket hole to a large pocket primer hole. Any help on this subject is appreciated….......…

 

[former naval person]

Problem you may run into is that the hardness of the brass in the head is (hopefully) precisely controlled. Forming the pocket gives a certain hardness...even the amount and depth of the head stamping is calculated to give the optimum hardness for resisting the pressures. Cutting the large primer pocket may change that parameter sufficiently to cause significant gas leakage, or even a kaboom. It may work on the ACP but pressures with that cartridge are much, much less than with the BIG boys. Be careful. Very, very careful.

 

[gvanhyning]

The .454 has a small primer for a reason and that is high pressure. I would not alter anything.


Sent from my iPhone using Tapatalk

 

[barryaclarke]

Hello again Gunny,

Thanks again for your insights and something that I didn't think about was the hardness of the head.

Barry

 

[barryaclarke]

Hello gvanhyning,

I was reading several write-ups that shows the 454 accuracy improves with the use of the LP. Maybe this is why they are cutting the 460 brass which produces the same pressure down in length instead of opening the pockets up on the 454 brass. Better to be safe than sorry, but it was just a passing thought on my part since I hadn't seen anything regarding this procedure. Thanks again............

 

[biffj]

The primer pockets could be opened up safely if you knew what you were doing. One of the wonderful things about brass is that the hardness is consistent until annealed. The case head hardness is uniform because only the neck and shoulder get annealed. By opening up the primer pocket you are not getting into softer brass....you can't surface harden brass so its all the same around the primer.
Having said all that its not a simple matter of taking a uniforming tool and making the pocket bigger. The tolerences on the primer pocket are very small in both diameter and depth so its going to require some precision machinery to do it right. One thousandth too big on the diameter and you may have primers falling out....one thou too small and they either won't seat or could go off when seating. Depth is important too because too deep and the firing pin may not hit the primer enough to fire, too shallow and you may have an unintended discharge on closing the bolt. In addition to safety reasoning be aware that accuracy of the round will depend on consistency in the primer pocket too. The few bucks you save on brass may go out the window if you're main intent is to improve accuracy.......


Good luck

Frank

 

[barryaclarke]

Hello Frank,

Thank you so very much for the very informative reply. I have ordered a .451 Bullberry barrel and they are running a few months behind. So, I still have about a month to make up my mind on what caliber I want. I'm now leaning to either shortening 460 brass to 454 or just buy the 460 barrel. Why do I want to use large primmers in a 454? Because I have I have read there is an improvement in accuracy in and in addition, I have seven boxes of Winchesters LR magnums on the shelf with nothing to use them in. Thus, I'm still on the fence about it.

Thanks again,
Barry

 

[Clark]

The 454 Casull has a small rifle primer pocket, but it does not need it. I have done double 454 Casull charges in 45 Colt brass with a CCI 200 large rifle primer while shooing it in a 410 shotgun [much thicker walls than a 454 Revolver]. 40 gr H110 400 gr.

The 460 S&W is not as popular as the 460 Rowland, in case others are as confused as I was on first reading.

 

[mavrickarcher]

The primer will still be in the center use what the brass came with.

 

[sakobob]

The 454 Casull has a small rifle primer pocket, but it does not need it. I have done double 454 Casull charges in 45 Colt brass with a CCI 200 large rifle primer while shooing it in a 410 shotgun [much thicker walls than a 454 Revolver]. 40 gr H110 400 gr.



how do you get them out of the chamber after firing them?

 

[Clark]

The .410 break action shotguns have an extractor/ejector that launches the empty many feet.