Russian unveiled the new Balkan 40mm automatic grenade launcher at IDEX 2009 (massive military expo held in Abu Dhabi that was on earlier this week).
The AGS-17 Plamya, the auto grenade launcher currently fielded by Russia, is 30mm. The new launcher extends the effective range from 1700m to 2500m and the larger round will of course give it more bite.
It is logical to compare it with the 40mm Mk 19 Automatic Grenade Launcher. The weight and rate of fire are much the same. The Balkan comes standard with optical sights and the Mk 19 can be fitted with sights if needed.
The ammunition is quite different. The Balkan uses Russian style 40mm grenades that are in a sense caseless. The primer ignites powder, the gas then exists through vents in the bottom of the case. This is similar to the infamous Gyrojet ammunition. Unlike the Gyrojet I think all the grenade powder is burnt before the round leaves the barrel, unlike the Gyrojet which burnt the propellant slowly and accelerated slowly.
Another difference is that the ammunition box holds 20 linked rounds and weights 14 kg while the Mk 19 uses 32 or 48 round boxes weighing 20 and 30 kg respectively.
Hat Tip: diva @ WAFF