I've only shot the .358 ARk out of a 10.5" upper.....I built a couple 16" uppers but they've been sitting here on the bench for over two years un-shot...
10.5"
1:14 twist
225 Barnes X
16gr lil-gun 1,583fps 356 power factor
17gr lil-gun 1,649fps 371 power factor
18gr lil-gun 1,728fps 388 power factor
10.5"
1:14 twist
225 Sierra 225 Game King
16gr lil-gun 1,579fps 355 power factor
17gr lil-gun 1,648fps 370 power factor
18gr lil-gun 1,725fps 388 power factor
7.62x39mm, 7.62x39mm (trimmed to length), .358 ARk (die formed), .358 ARk (fire-formed), .358 ARk (loaded)
