Based on the testing results gathered from the various different Leopard 2K prototypes, a new Leopard 2 prototype was constructed that would be more representative of the final version of the vehicle. Designated as Leopard 2AV, the new prototype featured a redesigned hull and turret over the Leopard 2K. Furthermore, the prototype was tested with two different cannons; the British L7 105mm rifled and the German Rheinmetall 120mm smoothbore cannon.
In 1976, the Leopard 2AV was sent overseas to the United States to be comparatively tested against the new American state-of-the-art XM1 Abrams. During testing, the Leopard 2AV proved itself as a good counterpart to the Abrams, outperforming its competitor in terms of fire accuracy, whilst demonstrating somewhat inferior protection and gun handling. Upon arriving back to its homeland with positive testing results, the decision was made to begin mass production of the Leopard 2 in 1977.
The production version Leopard 2, however, differed from the AV prototype in receiving an increased level of protection before mass production began. Mass production of the Leopard 2 started in 1979 with the Leopard 2A0 forming the first batch that would enter service with the German Bundeswehr in late 1980.
Throughout the production period of the early Leopard 2 versions, modernization and upgrades were being applied on the assembly line in order to keep the newest Leopards up to the latest standards. These modernization efforts mostly involved the upgrading of internal modules such as the aiming and communications systems. As a result of this, all early Leopard 2s (A0-A4) were visually neigh identical to each other. The Leopard 2A4 was the final early Leopard 2 variant before the more advanced and heavily upgraded subsequent Leopard 2 versions made their appearance as part of a new wave of modernization efforts.
A total of 695 Leopard 2A4s were built out of the total of 2.125 early Leopard 2s that were manufactured between 1979 - 1991. The Leopard 2 and its variants served primarily with the German Bundeswehr, but a number of export vehicles were sold to nations world-wide, ranging from Canada and Chile, over Denmark and Austria to Greece and Turkey to name a few.