I just got jumped over in another forum for even suggesting using faster powders in these short barrels due to unburnt powder. You get faster velocities out of the slow powders, but the efficiency is way down. Basically you waste several grains per round of powder that just gets blown out the barrel, when a faster powder burns cleaner and more completely.I do prefer slower powders, but only to the extent of where they burn clean and gives the performance I want.
N320,N330,Hp-38 or AA#5 are some that run that fine line quite nicely. I have used 3N37, N350, and even 3N38(impressive fireball) with good results in some high pressure wildcat calibers.
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