case stretching - What is normal

[egraham]

I have a remington 700 built with a 1/8 douglas match ss barrel. I bought 500 pieces of brass made from lc 5.56 brass. I trimmed them to 1.350 and then fireformed in my gun using 208 grain amax's at 1030fps.

How much should my cases stretch after fireforming? Do whisper cases need trimming after every firing or once fireformed do they tend to be ok for a few reloadings?

Thanks

[snipecatcher]

I'm up to 5 reloads with my current brass, and they are still ok. That being said, I'm going to both anneal them and trim them before they get reloaded, but so far, this cartridge has been a joy to load.
-Dan

[egraham]

What do you gain by anealing them?

[amafrank]

annealing is done only to the neck and maybe the shoulder area. It softens the brass there which otherwise would become brittle and crack from repeated working. The neck needs to be small enough to hold the bullet tightly and yet the chamber must allow the neck to expand so the bullet is released without excessive pressure buildup. This works the brass which work hardens and becomes brittle. I've reloaded some cases 7 or 8 times with no annealing and I've been trying to find a limit which has not been reached so far.

As for stretching cases I've found that those I've loaded supersonic tend to stretch a few thou and need to be trimmed after a couple shots while those loaded subsonic haven't needed trimming in 6 or 7 shots. The higher pressure causes the cases to flow more and results in stretching.

Hope that helps
Frank

[egraham]

Thanks. I never knew. I just know that the Lapua cases I use for all my other rifles are annealed from the factory.

[320pf]

All brass is annealed from the factory. However with 300-221 brass made from 223 REM cases, trimming/cutting the case back to 1.35 inches removes the annealed part of the 223 REM case.

I shoot an AR so with case loss due to ejected not finding all the the spent cases I figure I reload some cases at most 3-4 times.

With a bolt gun you should not lose many cases in the grass etc... so you should anneal them after about 2-3 reloads.

320pf

P.S. You can get a nice annealing kit from Hornaday