As the tin says. In the budget battles of 1980, some obscure, never to see the light of day project looks a bit more promising and sucks up more black budget funding hidden in 400 dollars a hammer deal. Unfortunately, it forces the axing of the M1 series. However, it is decided the turret design of the M1 will be incorporated into the next upgrade package of the M60 series resulting in the M60A4. M60A4. Uprated Diesel Engine, Chobham Armor replaces the old armor but still same chassis, new NBC system, turret from the M1, 105mm rifled gun later replaced with 120mm rifled gun so it has a more versatile use than the overkill that was the M1 main gun that made it unsuited for Close Infantry Support due to its enormous muzzle blast. It also retains a phone for accompanying infantry to talk to the TC, and instrumentation to serve as indirect artillery in a pinch. Okay discuss.