Propane indoor is not much of a problem, but it smells for a while. Lightning a candle AFTER you are done shooting helps remove the smell but its not perfect. I would look into a CO2 pistol, usually it doesn't smell, though sometimes it does smell a bit of car exhaust when using weird brands CO2 caplets. The smell doesn't last like propane though. Also, CO2 GBB pistol usually have more recoil, so it sounds like exactly what you are looking for. KJW makes CO2 versions of their Berettas, you should look for that.
Keep quiet. Sound travels faster than BBs.
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