- Up to six casings can be found on the dead body of any enemy that was wielding a .45 Auto pistol or a .45 Auto submachine gun at the time of their death.
- After the completion of Honest Hearts the casings will also begin appearing in the main game at the Gun Runners' store, Quartermaster Bardon at Hoover Dam offices and from traveling merchants.
- One can buy 30-50 at a time at the Gun Runners' store, and upwards to 200 at a time at the Great Khan armorer.
- In Zion Valley, .45 Auto cases can be found commonly in ammunition boxes.
- Zion Ranger station - In the trash bins, roof, and truck. Five around
- Zion fishing lodge's trash bins outside. Five in
- After the Honest Hearts add-on, traveling merchants will "sell" .45 Auto casings (among many other calibers), but they will always be for free. Likewise, if one tries to sell casings to a merchant, it will not yield any funds.
These casings can not be acquired before traveling to Zion Canyon even with Honest Hearts add-on installed, as they are not available with vendors, and no enemies will use .45 Auto ammunition before that point.