41 Mag
Member
I also have a couple hundred mixed once fired and some are 1.270" long. Is that going to be a problem? My manuals say the trim to length is 1.275". The majority is around that or a couple thousandths longer. But quite a bit is 1.270. I don't really want to trim it all to the shorter length... but do I have to?
What I normally do is pull out 20 - 30 and measure them, then trim for the shortest case of the bunch. Some end up being trimmed quite a bit some hardly get the mouth squared, but when done they are all right at the same length. I usually shoot these until they start to have split necks or seem to loose their tension then scrap them and start new again.
So in your case I would measure and find one that is 1.270" on the money, then set up the trimmer so that it just touches the mouth and possibly shines it up but doesn't take any off. Then I would run the whole batch through and call it good.