• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

243 primer pocket life?

Does anyone have experience with how long pockets should last on a 243 win.
I had two types of brass loosen up after 4-5 firings. Loads were up to 42 grains of imr4350.

Thanks for any help!
 
Whatever the brand of brass, case heads'll last longer if you back off a little on the propellant charge for the first firing or two.

Brass work-hardens with use, which is why some folks anneal case necks. At the back end that tendency to harden will help resist primer pocket enlargement... but only if you give it a chance to.

Loading up full-boat loads for the first firing will kill pretty much any brass's potential lifespan.
 
That's new to me.I don't run full hot loads that often but I will take your advice and see if it makes any difference.Thanks!!
spclark said:
Whatever the brand of brass, case heads'll last longer if you back off a little on the propellant charge for the first firing or two.

Brass work-hardens with use, which is why some folks anneal case necks. At the back end that tendency to harden will help resist primer pocket enlargement... but only if you give it a chance to.

Loading up full-boat loads for the first firing will kill pretty much any brass's potential lifespan.
 
Ive got 60 pieces of winchester brass that i've reloaded about 13 times. the primer pockets are still in fine shape. most of the loads have been 42.5 of H4350 over a 105 amax
 
I have Winchester and Remington brass that I bought in the 80s that I'm still using with way over 30 loads, maybe close to 100. The primer pockets are a little loose compared to new Norma or Lapua but they still work. At this age I have to anneal every time or I get split necks but no primers coming loose.
 
I have Winchester Brass . that has been ff into 6mm Competition Match with 20 times reloaded. I will shoot this brass once more then disspose of it. Simply because I feel it has served it purpose, and I have another 150 cases to finish the life of the barrel out.
 
there are things other than bullet weight and powder load that can cause pressure to open pockets.

seating bullet in or too close to throat for the powder/bullet combo
case needs to be trimed as chamber maybe short
case neck wall thickness to tight in chamber
mag or "hot primers
short or tight chamber from "new reamer" as they cut cleaner

back off on load and creap up.

Bob
 
spclark said:
Whatever the brand of brass, case heads'll last longer if you back off a little on the propellant charge for the first firing or two.

Brass work-hardens with use, which is why some folks anneal case necks. At the back end that tendency to harden will help resist primer pocket enlargement... but only if you give it a chance to.

Loading up full-boat loads for the first firing will kill pretty much any brass's potential lifespan.


Interesting...
 
IMO, primer pocket growth is tied to support the chamber/action provides.
'Hot loads' are relative to this and other support areas.

My reasoning; with sloppy chamber clearances around the web area, your cases will expand more in the web area. It's more case body expansion, but this provides a place for web brass under pressure to go(squish out).
They will shortly expand to yielding, which is not easy to undo if possible at all, given that we don't size webs. Even small base body sizing does not restore webs, but moves brass above webs, and there is no reason the movement would just happen to go back towards and restoring webs. So pockets only get looser(never tighter).

The breach end is also turned down & threaded, there is less barrel steel around the chamber, and threading to expand into. No doubt the chamber expands more & more nearing the breach than toward the shank.
And then there is little actual support for webs with rimless cases and typical bolt actions anyway.

There is a big crowd here that would preach otherwise, but consider actions to provide more chamber support for greater case life with higher pressure loads:
- Put as much barrel steel as practical around the chamber(magnum diameter action)
- Use tight clearances around the web area(with respect to new/unyielded case dimension)
- Where a choice, choose tight threading, finer thread pitch & shallower better threading for your action
- You don't want the first few threads carrying the load, and unloading on firing, so load all threading, and pretension away from the boltface(e.g. Savage barrel nut, remage)

Yielding can be managed to a stopping point that is not an end of case service.
It applies to all portions of our cases, with angle added as a factor for shoulders.
In other words, you can plan for longer brass life, with hot loads, but the plan would include a fitted chamber w/resp to NEW brass plus any improvements.

This is analogous with building of racing engines. It's not intuitive to accept, but racing engines employ very tight clearances, with very low tolerances.
The shade-tree days of sloppy clearances and accepted engine failure rates went out with Smokey Yunick's experimental NASCAR testing. Today, our manufactured engines are higher precision and last a lot longer because of his tested results, which were opposite of what everyone was doing back in the day.
 
Mikecr in principle I couldn't agree with you more. In practice though, with the nearly infinite variety of hardware out there the almost infinite number of shooters are using daily, it'll be a few who are in a position to build rifles to NASCAR specs while the rest have to do the best with what they have.

Your observation on rimless cases applies to both groups. The former however are more likely to be in a position better able to afford new brass on a recurring basis (when available at all!) than the latter.

My suggestion for 'work-hardening' new brass before employing near-max loads will benefit both groups but isn't a cure-all, just an accommodation.
 
But you can't work harden webs, much less primer pockets.
You're not sizing there, but only near there.

The only way to keep webs ~unchanged, is to prevent their changing from the git-go.
This applies everywhere else just the same.
If you were to 'fit' a chamber to a new case of improved/modern design(~<1thou clearance everywhere), put enough supporting barrel steel around it, and running within SAAMI max, it's possible to keep the brass from ever changing. It would operate within springback, never yielding, and it wouldn't need to see a resizing die.

Like a threaded stud; if you keep it clean/lubed, and never stretch it to yield force, it will last forever in it's restorable form(as new). If you ever take it to yielding, even once, it's form is forever changed, and will change with every cycle from that point. This condition, while not ideal, is accepted as one use only in many industries.

All I'm saying is where pockets are loosening it's either part of our plan, a bad plan, or no plan.
In 35yrs reloading, and beyond max pressure testing, I have yet to take brass out of service due to loosening primer pockets. My max pressure testing is to find that line (which I simply stay below).
Choices..
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
166,719
Messages
2,224,142
Members
79,819
Latest member
Cinco
Back
Top