I'm new to Airsoft and this forum as well but not new to shooting. Got some great info in the newbie section and it led to more research and questions. Don't have an Airsoft pistol yet. Found that the Marui Hi-Capa's need to run on duster gas and their pistols have a plastic slide. Also found if you use Duster gas on the metal slide units like KWA, KJA, WE you'll probably get jams as it doesn't have enough power to operate it properly. In real 45's, you can swap out the recoil spring for lighter or heavier loads and it will operate fine. In the full metal 1911's, can you get a lighter recoil spring or make some type of modification so it will work with the duster gas instead of the more powerful green/propane gas? I'm looking to shoot in my basement and with the cold weather coming won't have windows open much and see the propane could be a problem without good ventilation. Are these GBB's using green/propane really intended as outdoor guns? Thanks!!