The M1A1 Abrams main battle tank is the most advanced western tank in OFP. It outclassed its counterpart, the M60, in all three areas: speed, firepower, and armour. An anachronism in OFP, the M1A1 Abrams was not adopted by the US Army until 1986. The realistic version of the Abrams for 1985 would have been the original M1, which had less effective armour protection, and an 105mm cannon, the same calibre as the m60's. It is present in several different variants and incarnations in OFP, ArmA, and ArmA 2, including Operation Arrowhead.