Trim length in measured chamber
Ok,so you've got all the numbers and it's time to trim the fireformed brass to YOUR chamber,what is the recomended spec to trim the brass while allowing for neck flow in the chamber?Will be loading Lapua and Win. brass in 308-155 Scenar-Varget.Waiting now for a Sinclair chamber plug to arrive to shoot the number and believe I recall around .025 from end of neck to end of chamber.So lets say your chamber measures 2.050,would you then trim to about 2.025?I plan on triming after each firing as I'm one of the 6 guys out there that don't mind the job and actually enjoy case prep.What say you? Old Grumpy Slow Bark
Re: Trim length in measured chamber
Once you know the "actual chamber length" that you'll get when you measure it with the "plugs", you may not need/want to trim at all. If I know that my brass is .025 or .030 shorter than the "actual chamber length" I won't bother to trim.
I havn't trimmed brass in a "long time". I neck size and shoulder bump so my brass doesn't grow. And more than likely your brass will probably be .020 to .040 shorter than the "actual chamber length". (Max case length) If you want to trim your brass, get after it. I'de rather be pulling the trigger. ;)
On my chambers,
6BR max case length is 1.560 and the "actual chamber length" is 1.580.
.221 Fireball max case length is 1.400 and the "actual chamber length" is 1.427.
22BR max case length is 1.560 and the "actual chamber length" is 1.585.
Trim your barss if you've got nothing better to do but like I said, I'de rather be pulling the trigger. ;D YMMV.
Re: Trim length in measured chamber
Bark I was always told by the old timers to trim .007-.010 so in your example it would be 2.043-2.040. I have always had pretty good results following this.
I started reloading some 35 years ago and the old timers then are no longer with us, wish I had picked their brains a lot more when I had the chance.
Re: Trim length in measured chamber
Simply trim all brass to match your shortest piece as long as it has adequate clearance. I usually go with 5 thousandths under the published trim length and hardly ever have to trim again before the brass is worn out.
Re: Trim length in measured chamber
Quote:
Originally Posted by kslefty
Simply trim all brass to match your shortest piece as long as it has adequate clearance. I usually go with 5 thousandths under the published trim length and hardly ever have to trim again before the brass is worn out.
+1
Re: Trim length in measured chamber
I trim to published and then make sure they are each exactly that length. That way I get more consistent neck tension when I neck size and load. More accurate....more consistent pressure.
Re: Trim length in measured chamber
Thanks for all the replys guys.Yep,I don't mind the brass prep and have found that all the little details transfer over to little groups.I'm with you Mikie on the trigger time,but I prep and load in the evening and every time I discharge the full 30 in the den it seems to upset the tropical fish ;D OGB
Re: Trim length in measured chamber
Quote:
Originally Posted by kslefty
Simply trim all brass to match your shortest piece as long as it has adequate clearance. I usually go with 5 thousandths under the published trim length and hardly ever have to trim again before the brass is worn out.
+2
Re: Trim length in measured chamber
Once you measure your chamber with the Sinclair plug,you'll find your virgin brass is far shorter than -.025.I never trim untill after the first fireing,then only to square up the mouths,taking as little off as I can,unless they reach within .024 of the chamber length.The loading manual reccomendations always seem to be much shorter than this.
Re: Trim length in measured chamber
Quote:
Simply trim all brass to match your shortest piece as long as it has adequate clearance.
EXPLAIN: :-\
Do you mean measure your fired brass and the one that is the shortest, make it your mark for trimming?
Re: Trim length in measured chamber
Quote:
Originally Posted by Dennis
Quote:
Simply trim all brass to match your shortest piece as long as it has adequate clearance.
EXPLAIN: :-\
Do you mean measure your fired brass and the one that is the shortest, make it your mark for trimming?
yes
Re: Trim length in measured chamber
Thanks for clearing this up!
Dennis
Re: Trim length in measured chamber
Quote:
Originally Posted by Joe O
Once you measure your chamber with the Sinclair plug,you'll find your virgin brass is far shorter than -.025.I never trim untill after the first fireing,then only to square up the mouths,taking as little off as I can,unless they reach within .024 of the chamber length.The loading manual reccomendations always seem to be much shorter than this.
Yep Joe,just pulled the new bag of Win.brass out and started measuring a few-2.006 to .009.Shorter than I expected.Will trim to match the shortest an then fireform and get after it.Going to leave the Lapua brass in the box till I get up to speed on what the rifle wants and then drop .5gn and play with the high zoot cases.This is fun,eh?Just like it's supposed to be.Sometimes I forget that ::) Old Grumpy
