A pistol is considered a close range secondary - and a lesser accurate one at that.
If a field has a FPS limit, the pistol must also meet that limit.
It's no fun, being shot with a hot gun. It's even less fun being shot up close with a hot pistol where he/she may be aiming for your chest, but ends up shooting you in the face because of lesser accuracy.
Indoor public field/venues are usually 350 fps. Outdoors can range anywhere from 350-425 fps.