Ammo can be resupplied by Engineer's Ammunition Package Ability
The Underbarrel Grenade Launcher — rail attachment, that allows to shoot high explosive grenades with a small blast radius, that detonates on impact.
The launcher comes stocked with 2 grenades, one in the chamber, and one in reserve. There is no way to carry more than two grenades, even with a Grenade Bandolier or Ammunition Belt. The splash range is lower than normal grenades, but it has the capability to kill any infantry in 1 shot (Direct Hit) and MAX suits in 3 shots. The ammunition can be replenished by engineer ammo packs (enabling Engineers to have an unlimited number of grenades available to them, which allows them to provide artillery support) or infantry terminals.
Launched grenades must travel 15 meters, otherwise, they will not explode. If the grenade does not explode, it will still do damage on a direct hit (usually enough to kill someone with fairly low health). The grenades do light damage against tanks, and do rather significant damage against aircraft, with 2 shots usually being able to take out an ESF.
To buy the grenade launcher, you must have the standard faction carbine with the S in its name: Gauss Compact S for the NC, TRAC-5 S for the TR, Solstice SF for the VS or the standard faction assault rifle with the S in its name: Gauss Rifle S for the NC, T1S Cycler for the TR, Equinox VE2 for the VS (note the Equinox does not have an S) or Battle Rifles. It is found in the rail slot. It can be obtained using certs or Daybreak Cash.