Stock KSC barrel is 6.14mm. 8-O ??????
Well, interesting thing pointed out to me by Illusion, my G19 shoots 341fps using 0.20g BBs, but same mag same minute shot 265fps using 0.43g BBs (had 0.43g loaded and dumped a few to load 0.20g BBs in order to chrony that game day......... was around +28C or so). That is only a ~70fps drop. My CA M24 shoots 0.36g BBs almost exactly 100fps lower than 0.20g BBs. A heavier BB will be slower to get moving in a gas powered gun, therefore the gas has more time to expand. Illusion figured that with the gas expansion properties of propane pushing a heavier BB that much, it'd roughly equal about the same pressure needed to push a 0.20g BB at 380fps.