In Original, Deathmatch and Team Deathmatch modes, the maximum ammunition can be carried is 40 (2 full reserved magazines, costing $130) for drum shotguns and 32 (4 full reserved magazines, costing $260) for other shotguns.
In Zombie Scenario, the maximum amount is 600 rounds, which can be grouped into 30 drums, costing $1950 for drum shotguns and into 75 magazines, costing $4875 for other shotguns. This also applies in Human Scenario.
- In real life, the 12 Gauge has 350 pellets in one round of 12 Gauge if the round is a birdshot round.
- In China version, the '12 Gauge' word is spelled incorrectly in M3 description.