The double barrel we used at the NTI would flip on the safety, IIRC when you reloaded. Screwed me up for a bit. We didn't get checked out on it. Just pick it up, figure it out and go. We had another mystery gun stage with an AK which I never fired. Since I knew that was coming (told us to bring ammo - for guess what), I had my Viet Nam vet friend with one, check me out first.