The M870 is an American 12-gauge pump-action shotgun designed by Remington in 1951. It entered service with the United States Marine Corps in 1966 and today, its more modern variant, the 870MCS (English: Modular Combat Shotgun) is currently in service with the United States and Australian military.
In multiplayer, it is the default shotgun issued to the American "Demolition" kit and has an 8-shell capacity. Like all pump-action shotguns, it is very powerful, being highly capable of killing in a single shot, but its efficiency deteriorates quickly at longer ranges. It is also limited to a low rate of fire, requiring the user to pump every shot. When possible though, the 870MCS might be preferable over other pump action shotguns due to its faster pumping action and therefore rate of fire.
The 870MCS in Battlefield: Bad Company in the multiplayer Valley Run
In multiplayer, the 870 Combat is the first shotgun available to the player. It acts much like the one in Battlefield: Bad Company, only its rate of fire is higher, it has a default capacity of 4 shells, and increased range. If used with the Extended Shotgun Magazine, it can hold 8 shells, making it much more effective in large scale combat.
The 870 Combat has exactly the same stats as the NeoStead 2000 and SPAS-12 in terms of damage, damage multipliers, accuracy, recoil and rate of fire, though it has a slightly faster reload than the SPAS-12, and a slower reload than the NeoStead 2000.
In Battlefield: Bad Company 2: Vietnam, the 870 Combat is a confirmed weapon, issued to all kits. Its appearance is much more rugged and rusty, with cloth strips holding parts together. It also has wooden furniture, as opposed to the plastic and metal design of the base game, which DICE has confirmed to be an art style for the weapons of the Vietnam expansion. It performs similarly to the 870 Combat in the base game, but it has higher damage up close. It has a default capacity of 4 shells and can be modified with the Extended Shotgun Magazine to have 8 shells.