GLOCK 17 Gen. 4 Full Blowback .177 Caliber BB Gun Air Pistol - TOPHATTER'S ARMORY DEALSThe GLOCK G17 Gen 4 CO2 Blowback air pistol brings all the features you want in an air pistol to one of the most recognizable platforms on Earth. Powered by an easy to change 12 gram CO2 capsule, this full blowback G17 Gen4 launches . 177 caliber steel BBs at 350 FPS. This airgun also features an 18 round drop free magazine that houses the CO2 power source Get the most of your training session with the realistic blowback slide action from this GLOCK.