"A shotgun would be ideal, though I’d settle for a .22 rifle"

A shotgun is a long-barrelled metal weapon that shoots out shot, or a lot of small metal bullets, when the trigger is pulled. It is designed to be fired from the shoulder, and the shot is stored in a solid projectile or slug, which disintegrates, setting the shot free to do its damage.

A .22 Rifle
Permission Granted by Copyright Owner for Use on Book DrumA .22 Rifle - Credit: http://www.adamsguns.com/

A .22 rifle, although also featuring a long barrel, shoots out a single bullet, and allows for a more direct aim and shot. It is also designed to be fired from the shoulder, but its barrel has a pattern of grooves cut into the barrel walls. The grooves contribute to angular momentum, which improves accuracy and range.