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I bought some brass in 270 Win and all of it was fired before, all different case lengths. The longer ones I trimmed to trim to length no problem. The ones that are shorter than trim to length- are they usable?
In This type of bottle neck round and in these short cases I imagine some other guy trimmed them too short. I cannot think of another reason why brass would shrink. I am not reloading them to max anyway so it won't be an issue of compressed charge. I can give you the exact measurements but don't have the notebook handy right now. Thanks.
07-28-2011, 11:48 AM
Ignore the differences, Joe, unless you are crimping. The variation will not effect the accuracy of the guns typically chambered for that round. ... felix
07-28-2011, 12:59 PM
Correct. Ignore unless they are too long. If too long, they can actually get pinched on the bullet and cause excessive pressure. Each gun would vary as to where that was and most have so much freebore that it is impossible. Likely the brass was too short from the original manufacturer.
07-28-2011, 02:00 PM
I have been re-sizing mil usrp 308 brass to 243 for many years now. The case necks are always significantly shorter yet they are as or more accurate than correctly trimmed factory brass.
07-28-2011, 03:43 PM
I bought some brass in 270 Win and all of it was fired before, all different case lengths.
In my experience,this is completely normal. In any batch of empty cases, ( Including brand new unfired. ) there will be a significant number that are already shorter than "trim to" length.
If you are fanatical about equal length, trim them all to a compromise length somewhat shorter than "Trim to" and discard those that are even shorter.
See felix's comments above
The most accurate rifles I have ever owned (the few that shot 1/4 to 3/8 groups) don't give a fig about .020 difference in case length.
Thanks that was a big help. Any crimp I am doing is very slight just to take away the expansion of the Lee Universal expander die and I am crimping to the crimp groove on lyman 280473. I have seen the same thing with 243 cases too so I guess the same principle would apply?
07-28-2011, 08:06 PM
As long as there is enough neck to hold the bullet and you're really "concerned", then trim them all to the shortest length so you start them all "equal."
Check your neck thickness, too.
07-28-2011, 09:21 PM
I bought a thousand 270 brass new, same lot number, and there was at least 0.003 from the longest to the shortest.
07-29-2011, 12:22 PM
Go with what Felix says!
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