Simply don't show up to the field with a hot sniper rifle. Most of the time snipers will have increased FPS limits however that is at the cost of increased Minimum Engagement Distances.
In fact I believe that Stalker or someone actually plays with a sniper rifle that shoots 360-380 FPS (on .20's) and brings it down even lower with heavier BB's. So really all you need to do is bring a gun that isn't hot on the field and you can play with anything you want. Hell you could even use a straw and some BB's as long as you don't blow the BB harder than 1.48 Joules.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE