Be kinda fun, wouldn't it? Nobody'd hafta travel too far, nice relaxed atmosphere (well, someof us, anyway), lotsa smoke an' boom, ya could dress up all funny or not...only thing makin' it different from a real old-timey shoot would be the missin' bar'l o' whiskey.
It could be handled like the postals that NMLRA an' NRA run, but shouldn't be limited to members...this is a good way to get new members.
You could run a little "Meet a BP Gun" booth, where newcomers could come up an' take a shot or two. Ain't EVER seen a first-timer shoot a BP weapon that he didn't come away smilin'.