Smallest? About the size of a desert eagle. Maybe with a little more heft. Forget to mention; I could also give an explosive flechette launcher, if you would prefer that. Basically, it's a gun that fires spiked bullets, or "darts" that get stuck in the opponent, rather than a conventional bullet passing through. The flechettes will be fitted explosives as well, so you'll be firing a mag of explosive spikes.