TAC, TAC & TAC!
It meters exceptionally well and is more accurate in my M14 than 748 (good accuracy) or 3031 (great accuracy). 168gr Sierra HPBT consistently sub-MOA, LC match brass w/Federal match primer, shot it in service rifle when I shot M14s.
TAC is also the choice of many of the AR-shooting service rifle guys out here, too. That alone was the reason I went with it at first, and haven't looked back. For price, I may order some bulk surplus 844 or 846, but this will be my primary powder for .308, and it will be well-used in .223.
Its accuracy is really great, working from smaller bullets in the AR up to the heavier ones, although I'm not sure of the grains exactly for the 600-yd loads. Plus, it's advertised as being less affected by outside temperatures, giving more consistent chamber pressures & performances across a broad spectrum of temperatures. Important in a place where you can shoot in the snow or greater than 100 degrees, depending on the season.
Can you tell I like it?