The Yugoslavian 60mm M57 Mortar was generally based on the design of the US 60mm M3 Mortar.  The breech piece, which is threaded into the barrel, has a ball fitting to mate into a rectangular base plate.  The mortar is a conventional drop-fired mortar with a fixed firing pin. The bipod has a cross-leveling gear operated by a threaded sleeve between one leg and the elevating gear. This is attached to the yoke, which carries the traversing screw and the shock-absorbing spring cylinders. The 60mmM57 is fitted with the NSB-3 sight. The sights are produced by ZRAK in Sarajevo, Bosnia http://www.zrak.ba/ others are produced in Iraq.

60mm M57 Data

Caliber                         60.75mm
Barrel Weight               5.5kg
Bipod Weight               4.5kg
Base Plate Wight          8.85kg
Sight                             1kg
Projectile                      1.35kg
Muzzle Vol.                  159m/s
Min. Range                   75 meters
Max. Range                  2,540 meters
Rate of Fire                  25-30 rds/min

Below: View of the 60mm M57 (De-militarized) and its NSB-3 Sight.

Below: Close-up of the NSB-3 Sight

Below: A second Yugoslav 60mm M57 in the collection. This one is "live" and registered with BATF.

Below: Side view of the "live" Yugoslav 60mm M57.