I made a 0.177" barrel attachment for this thing, at a 20x mix it was pushing 0.35 gram BBs to just over 1800 feet per second :D that's 39 ft lbs of energy! https://www.youtube.com/watch?v=23-DWhJ0-MA The same barrel hooked up directly to the air cartridge at 2500 psi yielded 1143 fps, still impress...