The M68 rifled gun is basically the barrel of the British Royal Ordnance 105 mm L7 gun altered to accommodate a revised drop block breech mechanism. One of the main changes is that the barrel is secured to the breech by a tapered pin and interrupted breech threads which allow the barrel to be removed from the tank shield without having to dismantle the mantlet. Firing is electrical only.
With the phase out of the M1 MBT from the regular US Army late in 1996, there are no longer any 105 mm armed MBTs (for example M48A5, M60/ M60A1/M60A3 and M1) in front line service with the US Army.
Production as required. Installed in the M60, M60A1 and M60A3 MBTs; M48 rebuild (South Korea); K1 MBT (South Korean development); M1 Abrams MBT; M48A5 MBT; and the M48 (Spain, Israel and Iran - equivalent to M48A5). It is also fitted to the Israeli Merkava Mk 1 and Mk 2 MBTs. It has also been fitted in many M48/M60/ Centurion MBTs upgraded by Israel.