Tank origin

Even though at the time of its debut the M1 Abrams represented a leap in development over its predecessors, it still received numerous upgrades to remain competitive in battle. The M1A1 variant, introduced in 1985, replaced the M1’s 105mm gun with a 120mm smoothbore cannon that was a refined version of the gun in use on the Leopard 2. The M1A1 also featured a new turret, upgraded suspension, and, in the final model, depleted uranium armor. It remained in production through 1993.