The Gatling barrel trades small penalties in damage, range, accuracy and stability for a large increase in rate of fire. Overall, this increases the DPS of the weapon by a substantial amount. In fact, Gatling weapons tend to be the highest-DPS weapons in the game, aside from weapons that can kill instantly such as sniper rifles. As such, Gatling weapons (full-auto rifles in particular) are used very widely in the competitive scene.

Gatling Barrel
Chassis Assault, Pulse, Beam
Type Barrel
Released On Jan 31st, 2014
Damage -1.55
Rate of Fire 6.67
Reload Time 0.00s
Clip 0
Range -20
Hip. Acc. -9.88%
Aim Acc. -15.54%
Stability -2.82%

*In comparison with the default weapon parts.