I'll go #2. That sounded wrong.
We could raid the Wheelgunners for members, and include traditional blackpowder shooters.
But since Single Action Shooting Society (SASS) is probably the copywrited name of a business, I think the more general term Cowboy Action Shooting would be better.
We should also open it up to Civil War re-inacters and buckskinners, in fact everyone who is interested in American shooting before WW1.
Why did you shoot him 68 times? "Because we ran out of bullets"-Sheriff Grady Judd