Have shot thousands of rounds of 8.0 grains Unique with 240-250 grain lead swc bullets in sixguns, great casual load. But for rifles, it's like the other posters said, you're just not going to get top-drawer performance out of Unique. Burn rate is too fast for that, and a carbine-length barrel can definitely take advantage of all a slow-burning powder like 2400, H-110, N-110, or 4227 can provide.