From Halopedia, the Halo wiki
The CQS48 Bulldog otherwise known as the CQS-48 Combat Shotgun is a type of human Shotgun manufactured by Misriah Armory in Eos Chasma. It appears to be in service with the UNSC, as well as being employed by Banished-affiliated jiralhanae in 2560.
The CQS48 Bulldog is a pump-action combat shotgun which fires 12-gauge shells from a 10-round rotary magazine. After every shot, the foregrip must be retracted and pushed forward again to work the weapon's action and rotate the cylindrical magazine into the next position. The rotary magazine allows the CQS48 to replenish its supply of loaded ammunition substantially faster than the non-detachable magazines of the M45 and M90 shotguns. However, the 12-gauge ammunition it fires is substantially smaller. The Bulldog integrates ironsights and multiple attachment rail segments on its body. The CQS48 used in 2560 features a matte black and dark grey finish.
The CQS48 has ready ammo count of 10, with a reserve of at least 20. The pickup prompt indicates that the CQS48 is a "shotgun", with "kinetic" and "spread" properties.
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