Reloading question on 40 S&W

[nwb01]

I am very new to reloading and have a couple of questions. I plan on reloading some 40 S&W rounds and have notice in a couple of manuals that the "trim to" length differs from book to book by about 0.010. So, I guess my question is.... As long as the cases are shorter than the max case length (0.850) is trimming required?
Or is it best to measure the respective barrel to see what the actual case length needs to be?

Does the "trim to" length really matter as long as the max case length and the over all length are within tolerance ?

Thanks in advance,

Nick

 

[Jim Watson]

Few autopistol cases ever require trimming. Most are shorter than max when new, and short straight cases will actually shorten in use, the expansion is going into diameter instead of length.

Load 'em up and shoot.

 

[bfoster]

Nick,

Jim is correct, normally you'll not need to trim most auto pistol cases.

As I see it, the only valid argument for trimming autopistol cases is to obtain the most uniform crimps possible; this may only be useful or "needed" for ammunition used in competition.

Bob

 

[stans]

Well, I once trimmed 1000 pieces of 45 ACP. They were great! Made some really accurate ammo for my 1911 (only had one at the time). They are all gone now, lost every one of them, mostly during IPSC match shooting. I will never trim another semi-auto pistol case. It just is not worth the effort for something that is likely to be lost, besides, most of them are short to begin with!

Revolver brass is a whole different story.