Thankyou Shotgunjones for taking the time and trouble to supply this extensive information.
Found in Brownings blurb about 0.742" being "the ideal interior barrel diameter for back-bored 12 gauge", equating to 18.85mm. so these tubes would probably be proof stamped at 18.8
Are all of your chokes generally 0.750" bore at the threaded (breech) end as mine? or does a particular manufacturer tend to have a smaller bore at the breech end of its chokes? which would then reduce the step in my 18.7 mm gun
It seems the factory Browning flush chokes need tossing in the bin!
Thanks again
