The M829 is an American armor-piercing fin-stabilized discarding sabot (APFSDS) tank round. Modeling was done at the Ballistic Research Laboratory at Aberdeen Proving Ground, which was incorporated into the Army Research Laboratory in 1992. The round is specifically designed for the 120 mm M256 main gun on the Abrams M1A1 and M1A2 main battle tanks. The penetrator is carried by a sabot during its acceleration in the gun barrel. Variants M829 The M829 has a ballistic nose and five tail fins made of aluminum. It is carried in the gun tube by a three-piece aluminum sabot, which separates into three "petals" soon after the round leaves the gun tube. The propulsion system uses an obturating case base with a semi-combustible cartridge wall. It has a total weight of and a DU penetrator with a rod diameter, which reaches a muzzle velocity of using of JA-2 propellant. Its maximum effective range is . According to Jane's, the M829 is capable of penetrating of RHA steel armor at up to a range. The original M829 is no longer in production and has been succeeded by the M829A1, M829A2, and M829A3. The corresponding training round is the M865, costing $1,121. M829A1 The M829A1 (nicknamed the "Silver Bullet" by Operation Desert Storm tank crews) proved itself in 1991 against Iraqi T-55 and T-72M tanks during Operation Desert Storm. The M829A1 round weighs and has an overall length of . The of JA-19 propellant creates a chamber pressure of , which results in a muzzle velocity of . The penetrator and its sabot together weigh . The mass of the penetrator alone is . The effective target range is . M829A2 The next generation ammunition, called 120 mm APFSDS-T M829A2, entered service in 1994 and is the armor-piercing ammunition currently being produced by General Dynamics Ordnance and Tactical Systems for the 120 mm M256 gun of M1A1 and M1A2 tanks. It is a technology improvement over the M829A1. The new ammunition's performance gains, while classified, result from several new features. These include a special manufacturing process that improves the structural quality of the depleted uranium penetrator. This, the use of new composites for the sabot, and a new propellant provide superior penetrator performance. Combined, these features increase the muzzle velocity of the M829A2 to approximately 100 m/s greater than the M829A1's (up to approximately 1,675 m/s) while operating at slightly lower pressure. The projectile's length