I tried everything to get this bullet to shoot in a 1:10 Douglas barrel and, even with the higher velocity of the 6MM-284, it didn't work. Interesting how these VLD bullets will not actually tumble when you don't quite have enough rotation - they just shoot very poorly. I now have a 1:9 Jeff Lawrence barrel in the 6MM-284 and it shoots 1/4" with the Hornady A-Max 105 grain. Been meaning to give the 107 Sierra a re-test in this new barrel -even though Sierra says a 8.5 inch twist is minimum for the .243 with this bullet.