Regarding shotgun shells, you do get what's referred to as solid slug, which is as the name suggests one solid cartridge, though considering military forces have been using shotguns it's more likely they are military issue. With pellets, you get buckshot, birdshot et, different sizes of pellet.

As a personal story, I do voluntary work in an Oxfam bookshop, one day at the bottom of a big box of old books was a metal box with about half a dozen rifle cartridges of two different sizes and the same with pistol rounds. Had to phone management then contact the local police.

I see Ryan is still a slime all.