Muzzle diameter guidelines:

Lightweight sporter = bore dia. + .250"
Medium sporter = bore dia. + .300"

Less than .250 ( meaning a wall thickness of .125 ) can be fussy

Last edited by RinB; 07/22/14. Reason: Spelling

“Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away”.
Antoine de Saint-Exupery. Posted by Brad.