When applied to a submachine gun, the mod greatly increases the weapon's total magazine size while reducing reload speed.
Weapon modifications will modify an existing weapon, and any modifications previously equipped on the weapon will be destroyed, not unequipped. Loose mods cannot be crafted. For modifications unlocked through scrapping, the corresponding weapon must be scrapped in order to learn how to craft it.
Learned when scrapping object
Large drum (1)
- The large drum mod may be crafted and applied to a submachine gun at a weapons workbench if the relevant plan is known. The mod can only be learned from scrapping submachine guns.
- Loose large drum mods may be randomly sold by Responder, Raider, Brotherhood, and Free States vendors. Loose mods can also be found randomly in various locations or earned as quest rewards in the Toxic Valley, Ash Heap, or Savage Divide.