Thread: .308 Norma case head expansion in R8

Hi there

I tested some 180 Interlocks in my Blaser R8 on the weekend. Norma cases, .308 cal. With 43 gn of 2206H, which is book max for Nick Harvey, i have expansion at the web of .004 ie from .467 to .471. I measured this parameter because I’ve been told that primer behaviour is not a good indicator for Blasers, due to the way the bolt operates. Anyway, is this much case head expansion normal or does it indicate excessive pressure? I don’t have much experience with using this parameter. The best group was with 42 gn but I need to chrony the loads to see what’s happening velocity wise.

Cheers guys