The AM-50 is a heavy smoothbore 120mm mortar. It is muzzle loaded and traverse and elevation are adjusted through the bipod. The AM-50 can also be fired from its fixed two wheel carriage when the axles are locked. The AM-50 was replaced by MO-120-LT.

The MO-120-60 is a lightweight mortar that is based on the AM-50. The base-plate is much smaller and the barrel is lighter. Although lightweight for a 120mm mortar the individual parts remain heavy for transportation by individuals. The MO-120-60 was supplemented with the strengthened and heavier M65.

The M65 is a strengthened version of lightweight 120mm M60 mortar. The M65 uses the same base-plate and mount as the M60. The barrel has been strengthened to reduce overheating and it allows the use of rocket assisted rounds. A special lightweight two wheel carriage with very small wheels can be fitted.

The MO-120-LT was introduced to replace the earlier AM-50. It is a conventional muzzle loaded smoothbore 120mm mortar. A massive triangular base-plate is fitted and the mortar is supported by a bipod that is adjustable in traverse and elevation. The two wheel carriage is detached during fire. The RS2M is a vehicle mounted version of the same mortar barrel.