This mod adds 30 rounds to the 9mm SMG's ammunition capacity, from 30 to 60.
- Alexander, 188 trading post
- Blake, Crimson Caravan Company
- Cliff Briscoe, Novac
- Dale Barton, The Fort
- Great Khan armorer, Great Khan armory in Red Rock Canyon
- Vendortron, Gun Runners kiosk
- Prior to patch 22.214.171.1242, the 9mm drums were only worth 500 caps.
- Vance's 9mm submachine gun already has a drum installed.