
When a soldier fires the M320, they will shout out a random grenade voice clip such as, "Throwing grenade!". Any kills with this weapon are added to your total number of frag grenade kills. Unlike the 40mm Smoke, the projectile does not deal any damage upon direct impact with an enemy. This version of the grenade launcher fires a 40mm LVG projectile which detonates after approximately 3 seconds, and is otherwise comparable to an M67 Grenade. The M320 LVG was added in the Close Quarters DLC. If no underslung rail is attached, it will still be an M320. Note that if it is equipped alongside the AK-74M, AEK-971 or AN-94 with the Underslung Rail attachment, it will turn into a GP-30 (with its own name in the killfeed), though this is purely cosmetic and does not affect gameplay. The leaf sights may disappear due to a rare glitch. The leaf sights do not appear to be accurate. Unlike previous Battlefield grenade launchers, the leaf sights can be used if equipped as a separate weapon. The grenade launcher occupies the Gadget 1 slot, which is shared with the Medkit and M26 MASS. It can fire multiple ammunition types including standard 40mm grenades, but also specialty rounds such as flechette and smoke rounds. It also has only four rounds, though the player can very quickly replenish the ammunition with the use of a Support player's ammo bag. Its blast radius is very small, such that one must land the grenade either on or just beside an enemy to gain a kill, limiting its anti-infantry properties. The arc of the projectile is far more pronounced than in older games, allowing it to go farther more accurately.
Weapon switch time is greatly reduced when mounted underbarrel, a tradeoff for the stability bonuses offered by other attachments. The M320 is an underbarrel attachment when the assault rifle's second slot is left empty (on the ' Underslung Rail' option), but is a standalone weapon when the second slot on the assault rifle is filled.
The M320 is an Assault gadget in Battlefield 3's multiplayer. On Rock and a Hard Place, an M320 is found attached to the player's starting weapon, the M416. This weapon takes up a weapon slot, and is not mounted to any gun. During Operation Guillotine, one can be found near a dead Marine in a crater near the canal just after mantling the wall. The M320 is featured only at certain points during the campaign. The M320 is a gadget featured in Battlefield 3. The M320 can be equipped on some Assault Rifles with the Underslung Rail." Initially developed for the G36 assault rifle, the M320 allows a larger variety of ammunition to be used with the weapon including Fragmentation, Flechette, and Smoke rounds. "A single shot 40mm Grenade Launcher, the M320 replaced the old M203 in service with the US Military.