A 12 Gauge Frag round is designed to burst on impact, littering the target area with shrapnel. Frag rounds are currently being considered for military use.
Battlefield: Bad Company 2
— In-game description
12G Frag Rounds is a primary specialization and weapon modification in Battlefield: Bad Company 2, exclusive for shotguns. It replaces the standard multiple-projectile short-range buckshot ammunition with single-projectile explosive round.
12G Frag Rounds can be found on the collectible TOZ-194 when equipped with slugs. It is the only shotgun in singleplayer to use the 12G Frag. Unlike in multiplayer, they have the same velocity and impact damage as slug rounds.
DICE-Boom is available only to employees of DICE for shotguns, with the DICE logo used as the specialization icon. The round creates large craters comparable in effect to C4.
The projectiles travel fairly slow, and the damage of the projectile is somewhat low. However, the addition of the splash damage from the explosion is able to put a decent dent into an enemy player's health. Due to the explosive nature of the ammunition, the player will take damage from the explosion if they are too close to its point of impact, and can potentially kill themselves if this done several times.
— Battlelog description
12 Gauge Frag is an advanced ammunition type featured in Battlefield 3 for shotguns. The explosions generated on impact increase potential Suppression, but also sacrifices accuracy and stopping power.
The frag rounds explode on impact, causing an explosion on target. This not only suppresses the enemy, but also leaves the opposing player in disarray as it is difficult for them to ascertain the direction of incoming fire. Players not under fire from the frag rounds however, can easily locate the shooter, as Frag Rounds produce a very large tracer, almost akin to that of the IFV main gun.
The addition of slight splash damage makes these rounds very effective for suppressing and killing grouped enemies, or enemies popping in and out of cover. It is also possible to kill enemies just behind cover by shooting the floor by them due to the splash damage. One example of this is on Seine Crossing, along the alley between the RU Deployment and Back Streets, where the splash damage and spread can be very useful.
Four hits from splash damage are needed to kill an enemy, or 2-3 direct hits. A pump-action can kill in one headshot at close range. At long range the spread of the rounds makes it hard to pull off a kill, as well as the fact that frag rounds are some of the slowest traveling rounds in the game. As an explosive weapon, it can set off other explosives such as anti-tank mines or C4 explosive.
The blast damage from frag rounds can kill the user if shot on the ground or a wall close to them. Four explosions will kill a player at 100% health, and the death will be considered a suicide. Frag rounds also have the ability to damage armored vehicles, including IFVs and MBTs. The blasts can penetrate through the windows on light armored vehicles such as the HMMWV.
The December 6, 2011 patch reduced the damage done by 12g Frag ammo when fired from semi-automatic shotguns. A separate patch reduced the rate of fire of the USAS-12 and MK3A1 when equipped with 12g Frag rounds.
— Battlelog description
12 Gauge Frag is a shotgun ammunition type featured in Battlefield 4.
Frag rounds do the least impact damage of any shotgun rounds, but deal considerable explosive damage within a small blast radius. If the explosion is within 2 meters of an enemy, four explosions will be enough to kill an enemy, while impact damage from direct hits will also contribute.
However, it has a very low muzzle velocity, at only half the speed of slugs, as well as heavy drop over range. Impact damage at long range is also very low. This means it is best used at medium range against groups of enemies, especially if they are behind cover or destructible objects where the splash damage will be advantageous.