M829 120mm, APFSDS-T
The 120mm, M829 series, depleted uranium armor piercing fin stabilized discarding sabot-tracer (APFSDS-T) is the primary anti-armor 120mm smooth bore, M256 cannon, tank ammunition in service with the M1A1 and M1A2 Abrams tanks. This second generation kinetic energy projectile is capable of penetrating the frontal slope of all fielded armor systems and it's high technology penetrator and sabot design provides a munition which is accurate at all combat ranges. It's primary function is the destruction of threat tanks and armor fighting vehicles. Target penetration is affected strictly by the high kinetic energy of the DU core when it impacts. Like other DU munitions, these are identifiable by their black color with white markings on the projectile (pointed) end. M829 series ammunition is loaded and fired in the normal manner. This ammunition will not be fired over the heads of friendly troops unless troops are protected by adequate cover as they may be struck by the discarded sabot.
The 120mm M829 Armor Piercing, Fin Stabilized, Discarding Sabot-Tracer(APFSDS-T), cartridge is a US developed kinetic energy (KE) armor defeating round. It consists of a fin stabilized subprojectile with a six bladed aluminum fin, a tracer assembly attached to the rear of the fin and a depleted uranium (DU) penetrator with a ballistic tip to reduce drag. The propulsion system uses an obturating case base with combustible wall. This growth potential round features a modern technology high length to diameter (L/D), depleted uranium penetrator, and lightweight sabot. The cartridge weight is 41.1 lbs. The major components of the M829 are:
- M829 Projectile
- Combustible Cartridge Case w/Case Base & Seal Assembly
- M125 Primer
- Propellant (JA-2)
- M13 Tracer
When the final series of Tripartite Trials - Growth Potential firings were scheduled for December 1977, the Ballistic Research Laboratories embarked on a program to further exploit the capabilities of the 105tmn M68 Gun. Their review of Picatinny Arsenal studies convinced them that the original 24mm geometry, modified to increase the L/O from 15.5 to 18.0, could be a functional, superior item. This basic design later evolved into the penetrator for the 105mm XM833 and the 12Omm XM829. Testing of the tungsten version of the XM829, in this case the 90% alloy, fired in the July 1979 Germany trials, demonstrated that despite occasional core failure at high temperature, impressive penetration performance was obtainable.
The US 120-mm. program to transfer the technology for the German-design cannon and ammunition neared completion and initial production started in 1984. The U.S. development of the XM829 Armor Piercing Fin Stabilized Discarding Sabot Tracer cartridge finished the full-scale engineering development phase and the program resolved major technical issues and completed the test phase of the Technology Transfer, Fabrication and Test program in that year. The Army continued its successful transfer of the cannon technology during fiscal year 1984 with Watervliet Arsenal fabricating 31 complete XM256 cannons and 56 spare tubes. Although the U.S.-made XM827 kinetic energy rounds with depleted uranium cores successfully passed accuracy and armor penetration tests, the Army decided not to produce them but to concentrate on the XM829 round. Program managers continued development of the XM829 cartridge with a successful test in Panama of straight wall cartridge cases and a DTII test at Aberdeen Proving Ground. As a result of these tests the contractor made improvements in the round and received approval for producing 8,500.
The M829 is no longer in production. It was replaced by the M829A1 and more recently by the M829A2.
The M829A1 (nicknamed the "Silver Bullet" by Operation Desert Storm tank crews) is widely regarded as the most effective tank-fired (M1 Abrams 120mm main gun) anti-armor weapon in the world, and overwhelmed Iraqi armor during Operation Desert Storm. The M829A1 is a depleted-uranium long-rod kinetic energy penetrator round capable of defeating heavily armored vehicles.
A Battelle Pacific Northwest Laboratory study, released in August 1990, characterized particulate levels with both complete and partial penetration of the armor after hard impact. Researchers tested both the M829A1 and XM900E1 rounds and two non-DU rounds, the M865 and DM13. The purpose of the non-DU round firings was to evaluate DU resuspension during hard impact tests. The sample results were questioned when the percent aerosolized was initially estimated to be only 0.2 percent to 0.5 percent for the M829A1 and 0.02 percent to 0.04 percent for the XM900E1, values approximately two orders of magnitude below the expected values. One of the first studies Battelle performed with the XM774 produced a value of 70 percent, which is frequently cited in the popular press. This study stated it was highly unlikely more than 10 percent of the DU by weight aerosolized on impact. Duplicating other study results indicating a high percentage of the respirable dust from hard-impact testing was soluble in the lungs, this study indicated 57 to 76 percent of the respirable dust fraction was class "Y" material and 24 to 43 percent was class "D" material. (Class "D" materials have dissolution half-times of less than 10 days; class "W" materials have dissolution half-times of 10 to 100 days; and class "Y" materials have dissolution half-times greater than 100 days.) The resuspension tests indicated most of the resuspended dust was non-respirable, consistent with the theory the enclosure's filtering system removed most of the respirable dust.
As the executing arm of the Project Manager for Tank Main Armament Systems (PM-TMAS), TACOM-ARDEC recently fielded the M829A2, which enhances the round through increased velocity and improved terminal effects. The improved performance was attained by implementing new composite material technology and a new propellant with a higher loading density. The Cartridge, 120mm APFSDS-T M829A2 is the current production armor defeat cartridge for the 120mm gun tanks M1A1 and M1A2. It is a technology improvement over the M829A1, the "Silver Bullet" of Desert Storm fame. The A2's performance gains, while classified, result from several novel features. These include the use of new manufacturing process to improve the structural quality of the depleted uranium penetrator, the use of a carbon-epoxy composite for the sabot (a world-wide first in a projectile this large) and a special manufacturing process which partially cuts the propellant charge to allow it to behave ballistically like a granular propellant bed, while loading like a stick charge. Combined, these features increase the muzzle velocity of the M829A2 approximately 100m/sec greater than the M829A1, while operating at slightly lower pressure. PRIMEX is the sole producer of this advanced technology penetrator coupled with a state-of-the-art composite sabot and propulsion system. The M829A2 APFSDS-T KE munition is compatible with all standard NATO smoothbore 120mm tank cannons.
The M829E3 is the Army's next generation 120mm Armor-piercing Tank round. It replaces the M829A1 and the M829A2 projectiles. These rounds are widely regarded as the most effective tank-fired anti-armor weapons in the world. The E3 round will provide the army greater armor penetration capability than its two predecessors and also with improved accuracy. The M829E3 120mm Cartridge is an Armor piercing Fin Stabilized Discarding Sabot - Tracer. This Advanced Kinetic Energy Round that defeats advanced threat armor, with improved accuracy at greater range. This new 120mm KE round for the M1A1 and M1A2 Abrams fleet features a combustible cartridge, overall length is less than 986mm, Depleted Uranium Penetrator. Weight is less than 56 Lbs. and it uses RPD 380 propellant. The System Contractor is Alliant Techsystem, Inc.
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