New Lapua 6.5 CM case length variance

[6.5 forever]

My cases after 2-3 firings vary by 5 thou. My question is, do you trim all to the shortest case. I am 7 firings on a box and I trimmed to 1.915. Approximately half of the cases don't need trimming, with many still at 1.910.

How do you approach new case length variance?

 

[ronemus]

If you're pursuing high precision and already doing extensive work on your brass, trimming to a consistent length is probably the way to go - variation in neck length translates to differences in bullet pull force. If you're a more casual short-range (under 600 yards) shooter, you'll never see the difference and trimming to SAAMI minimum once in a while will do.

 

[47WillysGuy]

My cases after 2-3 firings vary by 5 thou. My question is, do you trim all to the shortest case. I am 7 firings on a box and I trimmed to 1.915. Approximately half of the cases don't need trimming, with many still at 1.910.

How do you approach new case length variance?

Set the trimmer to 1.915 and trim them all. The short ones will catch up.