- "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.
Regular vehicles can only survive two direct hits from an Explosive Shotgun before catching fire. 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 may also be noted in their ammunition capacities, while both variants are capable of holding 20 standard or explosive shells per magazine, the Automatic Shotgun can only hold 230 regular shells in reserve (the same carrying capacity as The Lost and Damned's Assault Shotgun, which can hold 8 rounds in the magazine and 242 rounds in reserve), while the explosive variant can hold up to 580 rounds in reserve. 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 like semi-automatics in a similar fashion to the Combat Shotgun in GTA IV.
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 the mission "High Dive" and again in "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 ".
- Luis Lopez asks Yusuf Amir for some more explosive shells in the mission For the Man Who Has Everything, because Luis finds them impressive.
- 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.
- Since it is a shotgun, it has the cocking animation of the Pump-Action Shotgun when blind firing, which is rather unrealistic 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 Sawn-off Shotgun from TLAD, while with the explosive ammo, it makes a unique sound.
Assault Shotgun, the Automatic Shotgun's successor.