Re: .32-20 BP loads?
I know one reason that the newer brass will only hold 21 grains of powder up to the top of the brass, it is solid headed brass. I have some old balloon head brass for the 32-20 that will hold 25 grains of 3fg powder to the top of the case, put only 20 in it and I have plenty of room to seat a 115 grain bullet. As for grease grooves, there is an old lyman design that has a very large grease groove in it, that should work well with black powder, but you will have to watch the auction sites for one as it is out of production.
Hope that info helps out,
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