i have a dual port varmint action in 223 ,im switching barrels to a 300wsm. i purchased a mag bolt head and firing pin assembly but the bolt head is a tad longer than the one that is in the dual port receiver.the bolt wont close, i haven't taken the 223 barrel off as of yet.do i need a special bolt head for the dual port or is it too long because i'm trying to close the bolt with the 223 barrel..