Re: 308 with a 16.25 barrel length
call it a gift, call it a curse, but memory says the last time this was asked here, it was stated you lose 50-75 fps per inch i believe. im running a 24" and dont own a chrono so its just what ive read. should give you an estimate if you know the starting velocities. hope it helps. search might turn up more, but its a tuff thing to get a keyword for