Here's some info:
http://world.guns.ru/grenade/gl23-e.htm
Caliber: 40x53mm High Velocity
Type: short recoil operated, belt fed automatic grenade launcher
Overall length: 940 mm
Weight: 18 kg gun body; 41 kg complete with Mk.108 tripod and AN/PWG-1 video sight
Effective range: up to 1700 meters against point targets, up to 2200 m maximum
Rate of fire: 225-300 rounds per minute