The 120×570 R cartridge was originally intended for the German Rh-120 smoothbore gun but an interoperability agreement signed between West Germany and France in April 1979, followed in September 1981 by a project to install the M256 120 mm smoothbore gun on future M1A1 Abrams tanks made it a NATO standard.

These incorporate a short, metallic stub case with an elastomeric sealing ring which allows the use of a normal sliding wedge type of breech and at the same time significantly reduces the weight of the rounds.

Thus, a round of 120 mm Rheinmetall APFSDS ammunition has a mass of 19.8 kg, which is little more than the 18 kg mass of a typical 105 mm APFSDS round with the traditional metallic cartridge case.

NATO uses the 50% (This means that 50% of the shell had to go through the plate), while the Soviet/Russian standard is higher (80% had to go through).

[74] The visible difference between the two cartridges is the Ammunition Data Link (ADL) interface rings on the base of the M829A4.