My only experience is with the factory Savage takeoff barrels, and they have shot under 0.37" for 5 shots, or better. My best 5 shot group ever was with one, in 6.5 Creedmoor, and it measured 0.165". The first four shots in that group were 0.020". I've shot two in 6.5 CM, and 3 in .308 Win. One of those is a 22" blued chrome moly with a muzzle diameter of 0.57".