Most airsoft fields and houses will limit velocity for safety reasons. An airsoft gun that is shooting “too hot’ or above the maximum speed allowed can cause injury to other participants. These fields will have a chronograph set up to measure the velocity. Don’t be that guy. You know, the guy who tries to use an airsoft gun that shoots too fast for the course. Injuring someone because you can’t play by the rules is a good way to get escorted off the property or kicked out of an event.