If you are going to shoot any of the regular SASS categories you'll need two single action revolvers, a shotgun of a period style, and a lever action rifle in a pistol caliber. You can download the shooter's rule books here:
SASS Handbooks
Being you have a 1911, you might even look into shooting Wild Bunch like Roger does. There's a separate manual for that. You can get by with one pistol that way but you still need a '97 Winchester shotgun and a lever action rifle.
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