I saw the rental packages and luckily I have spare m4 mags. I'd prefer cutting cost where necessary. Two p229 GBB with spare mags shouldn't be too rough. I'll have a slight ammo handicap, lol. My M14 shoots at 380 fps but the spring has yet to be broken in. It's only seen about 500 rounds. May level out around 365 to 375fps. I doubt they'll let me shoot 20+ hot?