I can install tubes for you. I charge $50.00 to thread barrels plus cost of tubes, $18.95 for Colonial Arms tubes. I use Colonail Arms tooling all piloted to you barrel, ie.. .725, .726,.727, etc. not measured at choke but 3 to 5 inches from muzzle. I can install standard, thin wall and twenty gauge chokes. If interested contact;
Alan Gardner
C/O Lock Stock and Barrel, Inc.
(724) 668-8265
Best times are between 12:00 and 5:00 eastern
P.S. These chokes are known as Tru-Choke style tubes.
Threads are .795 X 44 standard
.775 X 44 thin wall
.675 X 44 20 gauge