With the forthcoming TUSK add-on kit, an M2 or an Mk 19 grenade launcher can be mounted on the CROWS remote weapons platform (similar to the Protector M151 remote weapon station used on the Stryker family of vehicles). 2. A 7.62 mm M240 machine gun in front of the loader's hatch on a skate mount. 3. A 7.62 mm M240 machine gun in a coaxial mount. The coaxial MG is aimed and fired with the computer fire control system used for the main gun. The turret is fitted with two six-barreled smoke grenade launchers (USMC Abrams use an eight-barreled version). These can create a thick smoke that blocks both vision and thermal imaging, and can also be armed with chaff. The engine is also equipped with a smoke generator that is triggered by the driver.
The Abrams also has provisions for storing an M16 rifle or M4 carbine inside the crew compartment for when they have to leave the protection of the tank under potentially hostile conditions, plus Abrams crews always carry personal side arms, the M9 Beretta pistols. The Abrams is equipped with a ballistic fire-control computer that uses data from a variety of sources, including the thermal or daylight Gunner's Primary Sight (GPS), a laser rangefinder, a crosswind sensor, a pendulum static cant sensor, data on the ammunition type, ammunition temperature, and a muzzle reference sensor (MRS) that determines barrel drop due to gravity and temperature. The fire-control system uses this data to compute a firing solution for the gunner. The ballistic solution generated ensures a hit percentage greater than 95 percent at nominal ranges. Either the commander or gunner can fire the main gun.
Additionally, the Commander's Independent Thermal Viewer (CITV) can be used to locate targets and pass them on for the gunner to engage while the commander scans for new targets. In the event of a malfunction or damage to the primary sight system, the main and coaxial weapons can be manually aimed using a telescopic scope bore sighted to the main gun known as the Gunner's Auxiliary Sight (GAS). The GAS has two interchangeable reticles; one for HEAT and one for APFSDS ammunition.