Nearly 9,000 M-1s were manufactured during the 1980s and 90s. The U.S. Army and Marines only use about 1,600 now, with foreign operators accounting for another 1,500.
This works out to about 1 tank per 100 troops deployed in counterinsurgency operations.
The Army and Marines are considering scrapping plans for a next generation tank and instead upgrading existing ones for:
an M1A3 version of the M1 in the works. This would be a radical upgrade, compared to previous ones. It would even be possible to make the 62 ton M-1A2 a few tons lighter. This would involve a lightweight 120mm gun, which would allow for the installation of an autoloader, new fiber optic wiring, and new (and lighter) armor. A new engine and running gear would also save weight. The M-1A3 might get down to 55 tons, or less.
But the most important changes would be the new computers, communication, sensors and navigation gear intended for the unrealized FCS tank. The FCS vehicle was to use new heavy weapons, that fire guided projectiles to a range of 12 kilometers. These can also be mounted in the M-1A3.
The upgrade would be expected to stay in use for 40 more years.