The Drum Mag is an Attachment.
The Drum Mag has 2 effects:
1)When your Primary Weapon's ammo is depleted, you cannot reload the magazine. Instead, the only way to replenish it is through ammo crates or the Scavenger upgrade. This effect does NOT apply to Secondary Weapons. They still reload when empty.
2)For both your Primary and Secondary, the magazine size is increased to 210% (rounded up/down) of its original value. This applies even to weapons that never need to be reloaded, like the XMG, Vulcan, all Elemental Weapons and Experimental Weapons. Weapons that reload no longer have backup ammo, which means that their total ammunition is reduced by 30%.
For example, a Honey Badger goes from 30 mag size and 90 total bullets to 62 mag size (more than before), which is also its total bullet amount, less than before.
A DSR1 normally has 60 shots and never reloads. With Drum Mag, it has 125 shots (more than before).
Primary weapons that would reload when emptied no longer need to, removing a window of opportunity for your enemies to kill you. However, you now run out of total ammo faster than before and may need to pick up ammo crates more often. Be careful with secondaries, because even if they have much more ammo than before, they still have to reload.
While Elementals already have too much ammo to worry about running out, Experimentals greatly benefit from this Equipment with NO DRAWBACKS.
Combined with the Scavenger Upgrade or Equipment (cannot be bought, only won at the Slot Machine), you will never run out of ammo as long as you are not too wasteful. For powerful weapons like the Iron Curtain or Bennett's Doom, this is one of the most overpowered combinations of the whole game.
- Possibly mean as a replacement for the SFH2 Mercenary's Skill Ammo Feed, which gives his MG one massive clip with no reloads. However, the Drum Mag can be equipped for any weapon in SFH 3.
- Before V20.8, Drum Mag had a glitch when it was used with rocket launchers: it would give unlimited ammo along with no reloads.