I happen to be looking at 300 Savage and the trim to length is 1.861 and the case specification length is 1.871.

Can someone explain why the case trim to length is a tad shorter than the case specification length? And does it make that much difference as long as all are trimmed the same and less than or equal to the case specification length? Why or why not?

The case must be srorter than the max case length to avoid pinching the bullet in the end of the chamber but the "trimto" length is purely a matter of SOP (standard operating procedure) and not at all cast in stone.

Instead of trimming .010 under max I trim to .030 under and never trim the brass again as once is enough and I just don't like trimming the stuff.

As far as uniformity goes.....that is important only if you're going to crimp the bullets in the case. If you're not going to crimp then the length doesn't matter much as long as it's shorter than the max case length! Your cases can vary in length .050 if you want and it's not going to cause a problem!.....as long as they're not too long.

If you look at the complete spec package, you will find that the Minimum case length is .020 under the Maximum case length, and that (in the majority of cases) the "Trim To" length is 1/2 way between the 2, or .010 under Max length.

Once your cases exceed the Max length, you run the risk of pinching the bullet in the chamber and saying hello to high pressure as a result.

If your crimping, than having all your cases the same length is of benifit, but if you not crimping than, in practicle terms, it realy dosn't matter if the length varies somewhat (as long as your under the max length).

In a moment a 1000yd BR shooter will come along and mention how he get's a 1/4" smaller group (at 1K) by making sure that all his brass is trimed to a exact length vs letting them float around the "trim to" length. In that case, see my "in practicle terms" disclaimer.

Most chambers are .03" to .04" longer than the brass so there is little reason to trim at all except to square the case mouth and make them uniform.

One of the advantages of trimming them all to the same length after the first firing is they should grow at approx the same rate so when one needs another trimming it's safe to assume they all do. If they are just random length, one or more could well exceed the max length while others are within specs. After each firing, you would need to mike each case for length instead of a sampling.
I also believe uniform length aids accuracy because of the consistant bullet pull.

Thanks for you help.

[QUOTE]Originally posted by vapodog:
As far as uniformity goes.....that is important only if you're going to crimp the bullets in the case.QUOTE]
Has anyone tried their favorite accuracy load in diff. length cases to see the result? I would think that it would affect bullet/neck tension & start playing on the accuracy. Just a thought. I start w/ the brass trimmed to the same length & only trim when they start to get close to max.

Vapodog has a good simple way to not have to trim often and I doubt if anyone could tell any difference if there were .005 difference in a pet load. I used to trim to the book specs until I read the description of a little home made tool to find the chamber length so I made one by Varmint Als specs so I trim .010shorter than the chamber now.
Does it work better? It works and I trim more often. Works for me.