- 3 to 9 casings can be found on the dead body of an enemy that was wielding a 12.7mm submachine gun or a 12.7mm pistol at the time of their death. Great Khans and NCR Veteran Rangers typically carry a 12.7mm submachine gun and Veteran rangers and NCR troopers occasionally carry the 12.7mm pistol.
- Many Legionaries also use weapons that fire 12.7mm rounds such as the 12.7mm pistol and the 12.7mm submachine gun.
- In Zion Valley, these can be looted from many White Legs.
- When you fire a weapon chambered in the 12.7mm round, there is a 20% chance you'll get a casing.
- You'll get 25 12.7mm casings if you buy a 12.7mm case box.
- Occasionally some traveling merchants will "sell" 12.7mm casings (among many other calibers), but they will always be for free. Likewise, if you try and sell casings to a merchant, you will not yield any money.