I'd read the hype on this stuff, so I gave it a looksey in 45 Colt. Seems to work best in the lighter bullet weights. I did not care for it with my 255gr. LSWC's.......mediocre accuracy and lackluster velocity. The cowboy shooters I know seem to be turning to Titegroup for their 45 Colts. I find it to be a super powder for mid-range 45 Colt loads. I'd be surprised to see Trail Boss still around 10 years from now.