I've found to that TrailBoss is alot dirtier burning than some of the other powders I've used and still load with. It fills the case though when large capacity cases such as the 45 Colt are being loaded-one of the selling points of it. I've used all of the powders posted except Clays and found them to work very well. Unique can be a little 'dirtier' than the others, but the newer stuff is better than the old. Red Dot in the 45 Colt is a favorite, 6.0 grains works real well with either conical or SWC bullets. I started using Hodgdon's Titegroup around maybe 3 yrs ago for the 45 Colt and have had good results. One of Hodgdon's selling pts on it is that it was developed not to be sensitive to powder position in large cases such as the 45 Colt, 5.0-6.0 grains of it works well. Win. 231 or Hodgdon HP-38 will work, but they are better in the 45 ACP, suppose to be a little more case sensitive to powder position. Still load TrailBoss in the 45 Colt due to my personal 'glich' of liking to load using a variety of powders, never settling on one or two, even though I've tried 'to clean up my act'!