223 brass shrinking?

M855

Sergeant
Full Member
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Nov 29, 2009
399
1
50
East TN
Brass has 5 loading on it mixed dates of LC fired in the same Rem 700,trimed to 1.750 now all 50 rounds are 1.743-1.748 ,What gives shouldnt it grow instead of shrink,is it time to throw away this batch of brass
 

Victor N TN

Retired civilian fart
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Feb 16, 2002
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Knoxville TN
Re: 223 brass shrinking?

Are you sure about the trim dimension? What did you use to trim with? Did you measure after trimming? Most of the times I have seen cases shrink is the first time firing to fire form new brass to a specific chamber.
 

M855

Sergeant
Full Member
Minuteman
Nov 29, 2009
399
1
50
East TN
Re: 223 brass shrinking?

Yes im sure,used a L.E. Wilson trimmer,checked after trimming, this is the first time Ive seen the brass shrink it always grows a little after firing,used the same powder charge,primer and bullet the only thing that was different was the outside temp was in the low 40s
 

Victor N TN

Retired civilian fart
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Feb 16, 2002
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69
Knoxville TN
Re: 223 brass shrinking?

The outside temperature may have something to do with it. But like I said above, I've not seen this before.
 

DocB

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Jan 14, 2004
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CSG
Re: 223 brass shrinking?

M855,

My Lapua .223 and .243 quit growing after 5-10 firings, but this was in fairly tight chambered rifles. Even after annealing, they didn't grow any more. I cannot give a reason, just letting you know what happened.

HTH,
DocB