Destructive Device for me. I have a 12 gauge breeching shotgun with a 12 inch barrel & hope to purchase a 20mm rifle soon. At the SO, I had a various times:

M3A1 (our departments first automatic weapons in recent memory purchased in 1988 for around $75.00 each)
Thompson 1928 (Displayed on the Sheriff's wall 90% of the time)
M11 (Confiscated)
Breaching shotguns
Beretta M12

BTW, the Beretta was the only that ran properly.