Acceptable Case Length Variation

[JDinFbg]

I have not been able to find an definitive answer to this question, and the answer probably depends on how the rifle is being used (e.g., general hunting, casual target shooting, competition shooting, etc.). It probably is also dependent on whether one crimps the bullets or not. But, if one has a batch of brass and ALL OF IT is shorter than maximum, what amount of case length deviation in the batch (in thousandths of an inch) would prompt you to trim the brass? Would you consider this a constant number regardless of the cartridge, or could a longer cartridge like 30-06 tolerate more case length variation in the batch than a short cartridge like the 22 Hornet?

 

[edwardware]

. . . the answer probably depends on how the rifle is being used. . .

You just answered your question.

In my casual benchrest rifle, I value consistency so much that I had it chambered in a cartridge that reduces brass growth.

In my plinkers, I don't trim at all unless a piece sticks in the gauge indicating it's grown close to the chamber neck.

Edit: the one notable exception: revolver brass that's going to get a roll crimp for slow powder needs to be very consistent. Length variations are amplified by roll crimping.

 

[Bartojc]

If it was all shorter than max I may not trim it at all. Sometimes first time on a new batch I'll trim all to a consistent length just as a starting point but it's not necessarily needed. I load mostly hunting rounds and mixed brass range fun.

-Jeff

 

[AJC1]

How you trim may be just as big of issue. In bottle neck cases if you trim by oal your neck lengths will vary giving different neck tension. If you get a trimmer that indexes off the shoulder your neck lengths will be consistent but oal will vary. My trim plan is strait wall cases get trimmed by oal and by others are shoulder index trimmed.