I’ve used Trail Boss powder in a variety of firearms for many years – examples are .32-20, .38-40, .44-40, .45 Colt, .40-65, .40-70 Bullard, .45-70 and also several low power loads for modern cartridges such as .375 H&H Magnum.  It’s interested to note that Trail Boss is not necessarily a low pressure powder.  For example, if I were shooting 405 grain bullets in a Trapdoor Springfield, I’d say it’s not advisable.  I say that because the suggested starting load for 405 grain is 12 grains generating 971 FPS @ 24,500 CUP.  The maximum load is 13 grains for 1007 FPS @ 25,600 CUP.  Interestingly, with a 300 grain cast bullet, 14 grains generates 1199 FPS @ 14,400 CUP.  What a different 105 grains less lead makes!

I’m interested in hearing what others have to say on this topic.