Well as it so happens most outdoor fields allow up to 540fps with a restriction to either semi only or sometimes only single fire spring snipers and a minimum engagement distance.

Three I know of are Hells Survivors in Pinkney if you're around the middle of Michigan, Hole in the Wall if you're on the west side of the state, and lastly Action Paintball on the east side of the state but I'm not 100% sure on the field restrictions of Action Paintball.

If you were to give a new player a priority list for buying gear what would you recommend (gun,battery,pistol costuming, etc but not necessarily what brand/type to buy)?
Recommended minimum gear to begin playing pickup games?
Mil-Sim minimum gear set?
Must have equipment or recommendations for later on?