So me and a few friends are buying some airsoft guns for playing at my cottage. I have plenty of safe play space in the bush. approx 30 acres.... not like ill use it all lol. I want to know what a safe fps will be for play, I ordered a King arms M4A1.. I believe it will be shooting at 430fps? Im used to playing paintball at 300fps... My one friend wants to buy and mod a sniper to shoot 650 fps and use heavy bbs... I dont know much about size and weight about bbs and what they do to the fps. what is a safe fps we should be shooting at?