Gauss Rifle
The Gauss Rifle, also known as the XM34 CEMD Gauss Rifle in the Codex, is Engineer's primary weapon. It's an assault rifle like weapon with a large magazine, low damage, and can be effective at any range with good aim. Like all primary weapons, it can be reloaded infinitely.
5 ammo is restored upon killing a Marked Enemy.
Deals 20% less Weakpoint Damage for a total of 130% Weakpoint Damage.
Weapon Mods
There are 7 Weapon Mods for the Gauss Rifle, 3 Elemental mods that add elemental damage of the respective type to the weapon, 2 Stat Boost mods that increase Fire Rate and Reload Speed respectively, and 2 Functionality Altering mods that add Burst Fire and Piercing respectively.
To see more details about how Elemental Damage works, see Damage Mechanics.
Electric
Capacitor Overload
Increases Fire Rate from 300 to 420 rpm When combined with Burst Fire, Fire Rate increases to 739.2 rpm
Reload Speed
Increases Reload Speed.
Reload Speed 1.8 -> 1.08 seconds
Short Reload Speed 1.2 -> 0.72 seconds
Alternate Trigger Group
Changes fire mode to a Three-Round Burst, increasing Fire Rate to 528 rpm.
If All Shots hit a target, the Last Round will deal Triple Damage (can be different targets).
When combined with the Fire Rate mod, Fire Rate increases to 739.2 rpm
APDS Ammo
Projectiles Penetrate enemies, dealing 80% Damage to targets Behind Them.