The most common type of shotgun shell, 12 gauge rounds are the de facto standard for shotguns across the wasteland, corresponding to an 18.53mm/.729 bore. Purebore ammunition is the most popular and most durable shell brand to hit the wastelands after the Great War, loaded with leaden pellets that can take down humans, mutants, and monstrosities with equal ease. All shells have a print reminding the users that they are not for use by children under 3. Shoot responsibly!
Common and powerful, the shells would've been even better, if the executable bug didn't prevent the Armor Class modifier from being applied. However, it remains an excellent ammo type, due to the combat shotgun being available.