i would think because you are starting with a larger diameter bore before the choke. just a guess though. anyone else got any ideas? from what ive read with the 10 ga, i have an sp-10, shooting #4 you want around a .690-.695 , shooting #6 you want a little tighter like .675-.680

Edited by - gobble stopper on 02/21/2002 19:44:32