KNR UAG-40

     None: The Ukrainians had been using the Mk 19 AGL since the mid-2000s, but they were never totally happy with it, especially its weight.  Therefore, in 2011, design work began on a replacement for the Mk 19, AGS-17, and AGS-30 AGLs, especially to produce an AGL which is lighter, more handy, and still fired the NATO 40mm HV round.  Development was considerably hastened after the Russian annexation of Crimea in 2014 and the Russian invasion of Eastern Ukraine a few months later.  Combat testing of the UAG-40 began in late 2016, and it is now under full-rate production. The UAG-40 has made an appearance at several international arms shows, and Ukraine seems to be concentrating its sales force in the Middle East.

     The problem with an AGL firing 40mm HV from a lighter weapon is the recoil.  To do this, the UAG-40 uses a variant of the blowback system called Advanced Primer Ignition (API).  In the API system, the grenade is fired before the bolt is fully in battery and is still moving forward.  The gases producing a rearward impulse must first overcome the forward motion of the bolt, and this slows and then stops the bolt before it reaches the rear of the receiver. The bolt does not strike the breech face with the amount of power as most AGLs.  A hefty recoil spring aids in reducing recoil further, and a longer chamber also keeps the cartridge from being ruptured by the API system.

     The primary Ukrainian concern was accuracy over range, and as a result, the muzzle velocity of the UAG-40 is lower than most 40mm HV AGLs.  However, accuracy is increased by the lower recoil forces, and is also increased by a tightening rate of rifling in the barrel.  The inside of the barrel starts with 12 rifling grooves, increases to 18 grooves mid-barrel, and to 24 rounds at the last third of the barrel, so it is not like progressive rifling. A 15.75-inch barrel contributes to this accuracy while keeping the weapon light in weight.

     Weight reduction is accomplished by the considerable use of titanium alloys and carbon fiber.  The tripod/cradle, for example, is 80% titanium alloy, and the receiver uses a large amount of carbon fiber.  The tripod weight is only 40 kilograms, including an ammunition box in the cradle.

     The UAG-40 has a leaf site on the rear of the receiver, and also has a Picatinny Rail atop the receiver for mounting optics.