Shotgun shells - They are loaded with different sizes of shot depending upon what you are hunting. Bird shot, buck shot or even a single slug.
Standard 16 gauge shotgun shells.
HAVE IT CHECKED OVER BY A GUNSMITH FIRST!!!!!!!!!!!! It is an old shotgun.
air soft pellets
the m16 uses 5.56 caliber ammo
You need to submit the kind of firearm is it? Pistol, rifle, shotgun?
shotshell
.380 ACP
45+70 Government
It will be printed on the barrel
The HK 4.6×30mm cartridge.
18 or older
It is difficult to find even 10 gauge shotgun ammo today. I have my doubts if 8 gauge shotgun ammo is even made any more, but corrections welcomed.