So heres my dilemma, I cant seem to find standard bore diameters for 20ga. Ive seen .614 (Japan).615 and .617. I have a Winchester 101 in 20 and want to measure the chokes but not sure which diameter was used by Winchester. I understand patterning different shots for different patterns. I'm just looking for numbers!
Thanks guys!
Are you asking about 20 ga. in general or just Winchesters?
My take on it is that "standard" is kind of loosey-goosey. I have 20 bores that range from 0.616-0.627", and they come from three continents and span a hundred years of gun making. I see no commonality or pattern.
Yes Winchester, specifically 101's
I've got an original 101 20 gauge made in 1963. I'll measure the bores and chokes tomorrow and let you know what I come up with. My gun is IC/Mod, but I've never actually checked the constriction and bore diameter. Will certainly do so tomorrow.
Strictly speaking, .627 would be a 19, not a 20. And so marked on the barrel flats of a lot of European guns. I had a 20ga Sauer from the 1930's, A&F import, that was overbored like that--and marked as a 19.
Really interesting. Bore diameter is .614. IC choke is .609 (.005) and Mod choke is .603 (.011). Always thought it was choked tighter then that. FWIW, I've killed a lot of doves using this gun over the years shooting over water holes and such. Guess those more open chokes didn't hurt me any for sure.