Thread: .233 bad grouping

I can answer these as I was shooting with Dax (and he has probably forgotten that this thread exists ). Was warm to the touch, but not particularly hot. Twist rate is 1:9.
Shot a couple of three shot groups at 25 yards to get it on the paper, 2-3 ~1 MOA groups at 50 yards, then a .6MOA group at 100). Then the next 3 groups at 100 were all over the show. ~2MOA at best.

He was using a bipod and bunched up jacket as a rear rest. Using Barnaul 55gr except for the last couple of groups where we switched to the steel cased Hornady Match 55gr and I had a shot, but there was no improvement.

Scope mount was my first suggestion too - surely copper buildup wouldn't have that much of an effect after ~12 rounds?