From the two intro documents from two different BB instructors, you need a pistol in 9mm or larger for the course. No 22LRs. For a revolver, you'll need to contact your BB instructor. If allowed, you'll need a lot of moonclips or speedloaders and pouches for them on your belt. If you don't have all your gear, I would recommend borrowing a similar pistol from a buddy well in advance so you can familiarized yourself with the working, drawing/reholstering/mag changes before your class. You will need to practice your DA skills as your first shot after drawing will be DA. If you can't get a pistol in time, I would suggest signing up for the next course. That would suck.