Originally Posted by Varmint Hunter
I have always used the reloading manuals for the "trim to" length which is normally .010" shorter than the listed maximum length.
If I am match prepping cases I prefer to fireform them to my actual chamber before uniformly trimming the cases.
I would never trim to the shortest case length unless that is longer than the suggested "trim to" length. If the shortest case is excessively short; why ruin the rest of your brass to match it?
In non match rifles I have found no tangible benefit to trimming cases at all, at least not for uniformity. However, cases must be trimmed (at some point) to avoiding excessive neck length which could eventually lead to dangerously high pressure.
I understand your reasoning for saying that if the shortest case in a batch is shorter than the 'trim to length', why ruin the rest by trimming them all to match that one.
The major reason for doing so is uniformity among case length.Not all cases in a batch of brass is going to stretch at the same rate,especially if you are working up loads with that batch.
A few thou' shorter than the 'trim to length' is neither here nor there in the aspect of functionability of your firearm,the brass will normally shorten on the 1st firing anyway,as you stated above,it may be best to fire them in YOUR rifle 1st before trimming for the 1st time.
I personally don't bother with this even though I understand the reasons for doing so.
I trim ALL my new brass to the shortest case in that batch,which is normally no more than a few thou' under the 'trim to length'.
MORE importantly is cases that are too long from new,I have come across this more and more of late.I think that ammo company's are becoming slack in this regard,trying to save a few bucks.
I also don't understand your statement about 'no tangible benefit from trimming brass in non-match rifles,not for uniformity'.
ALL brass should have a square,clean mouth for loading purposes,whether it is for a match rifle or not.It makes sense,to start out a bullet squarely into the case,the case mouth must be square,and chamfered to accept the bullet.