Brass life

jmason · #1 06-22-2009, 08:51 AM

How do I determine when my brass has exceeded it's useful life before I have case head separation?

BountyHunter · #2 06-22-2009, 09:03 AM

Case head separation is a sign of improperly adjusted FL size dies and can happen in as little as 3-4 firings.

IF your dies are adjusted correctly to give .002 bump on the shoulders, case head separation will not be an issue.

As for the usefull life, you will see other signs depending on the pressure you are running and overall softness of the brass. Primer pockets will loosen and necks will work harden are the two most common.

Necks can be reannealled to lengthen life and less pressure will keep primer pockets intact.

I have run cases as many as 30x and Tom Sarver who set the IBS LG world record group at 1k with a 1.4xx inch group, 5x and 50 score had 54 reloadings on his cases at the time of the record and retired them at 80 reloadings (Lapua brass) and annealed after every shot.

BH

jmason · #3 06-22-2009, 10:14 AM

BH- I do anneal after 2-3 firings. I'm using Winchester brass. I'm on the tenth firing for the brass and all seems well. I just wondered if there was a way to measure the case wall near the base? If there is a method, how thin is too thin?

jimbires · #4 06-22-2009, 11:07 AM

I think this is what you are talking about . Jim

https://shop.rcbs.com/WebConnect/Mai...&route=C11J142

BountyHunter · #5 06-22-2009, 11:30 AM

Quote:

Originally Posted by jmason

BH- I do anneal after 2-3 firings. I'm using Winchester brass. I'm on the tenth firing for the brass and all seems well. I just wondered if there was a way to measure the case wall near the base? If there is a method, how thin is too thin?

OK, you can use a dental pic or bent wire and feel inside to see if you have any grooves where a separation might occur. However, if you do it is caused by improper sizing. Fix that first.

If the FL sizing is correct, there is no "thinning" of the walls.

BH

jmason · #6 06-22-2009, 01:03 PM

Thanks guys!

Jim- that link isn't working for me was it for the RCBS casemaster gauging tool?

BH- If there is no thinning of the walls how do you conclude it no longer useful. It can't last forever. Does it just get to the point you can't anneal it? (it won't become flexible anymore)

I'm probably not FL sizing right anyway. More often than not after I anneal and size I find my case necks have stretched out and need trimmed to be uniform again.

Mikecr · #7 06-22-2009, 03:24 PM

I don't believe FL sizing will correct thinning in the body..
For one, shoulder bumping doesn't shorten anything below the shoulder.
And second, sizing the body inward will not thicken the wall where it has stretched, anymore than elsewhere(so it's still the weak link).

I think it's a good idea to monitor it if your loosing brass(trimming). That brass came from somewhere, which came from somewhere, yadda, yadda.

I also think the only ways to address it, is to toss after so many firings, or prevent it to begin with.
There is a misconception that FL dies take everything back to a 'standard'. This is not true at all.
FL dies, like any other, simply squeeze brass where there is an interference fit.
There are so many things that affect that fit and take...