- "The low recoil automatic shotgun blends the power of a full shotgun shell with rapid fire to take down multiple targets easily. Explosive shells turn this already powerful weapon into a gun that shreds vehicles in their tracks."
- ―Description from the TBoGT website
Modeled after the MPS AA-12, the Automatic Shotgun is available with two types of ammunition: a more conventional version that fires buckshot, while the second one, more devastating, fires explosive rounds that can inflict heavy damage on vehicles.
It takes two to three explosive rounds to ignite the fuel tank on a normal vehicle while five to six rounds are required to takedown an Annihilator at low altitude. The rounds have massive concussive force, easily denting vehicles. The Automatic Shotgun can kill an enemy in one shot up close or strike an enemy down from a distance.
The regular Automatic Shotgun is a separate weapon from the Explosive Shotgun; this means that in order to switch ammunition, the player must discard their Automatic/Explosive Shotgun and lose their ammunition reserve (unless the weapon is picked up off the ground). Regular Automatic Shotguns are distinguished by red shotgun shells in the loading chamber, while Explosive Shotguns feature green shells.
Differences should also be noted in their amount of ammunition: while both variants hold 20 standard or explosive shells per magazine, the maximum amount of total ammuntion for the Automatic Shotgun is 250, whereas for the explosive variant it's 600. In terms of rate-of-fire, both variants fare identically, although neither of the variants fire fully automatically like the shotgun's real world counterpart or the Assault Shotgun (probably for balancing reasons). Rather, they behave semi-automatically, in a similar fashion to the Combat Shotgun.
The range on both variants is impressive for a shotgun. The buckshot variant has similar range to that of the Pistol, and will never take more than three shots to score a kill. The explosive shotgun has range outclassing SMGs, and will usually kill in just one shot, but occasionally it may require two shots, but never more. This advantage can be used against helicopters.
- Armando Torres gives the player an Automatic Shotgun with standard ammo in Corner Kids.
- The version with explosive ammo is received from Yusuf Amir in High Dive and For the Man Who Has Everything.
- The player can purchase the weapon from Armando for $1,250, plus $80 for 20 standard shells or $160 for 20 explosive shells.
- Available in Multiplayer.
- The Automatic Shotgun with explosive ammo spawns in Safehouse after completing 30 Drug Wars and High Dive.
- If the player catches fire or falls while holding the Automatic Shotgun and fires it, the weapon will become fully automatic, firing much faster than usual. Though this is a glitch, it is evidence that it was originally fully automatic, as no other weapon fires faster than usual in the same conditions. The rate of fire was possibly made slower to balance it.
- The gun was more likely given a semi-automatic firing mode due to its real world counterpart. The real AA-12 fires at over 300 rpms, nearly half to that of an AK-47, making this an extremely dangerous shotgun. With the real world accuracy, combined with Frag 12 shells, one could completely rip up opposition in both the single player & multi-player modes.
- Since it is a shotgun, it has the cocking animation of the Pump-Action Shotgun when blind firing, which is odd as this shotgun has no pump.
- Depending on the ammunition, the sound of the Automatic Shotgun will vary. With the standard ammo, it sounds like a Sawed-Off Shotgun, while with the explosive ammo, it makes a unique sound.
- The ejection port is on the wrong side in the HUD icon.
- Assault Shotgun, the Automatic Shotgun's successor.