I have 3 model 12 full choke guns, a 30" trap & a 28" field both have .730 bore and .035 choke ,a 30" 3" duck's bore is .731& a choke of .031.

Joe,

I have a pre-war M12 HD 32" solid rib. Weighs 8.92 lbs.

.728 bore; .695 at the muzzle .033 choke

Thanks, everybody, for the replies. It is interesting that there is some variance in constriction but a few of ours are quite similar. Frank, that is one beautiful shotgun. I just love the way the early models were configured and finished. I got mine with spring gobbler and Super X lead #4s in mind. Have to get to a pattern board soon.... Joe

Here is mine.

Joe,

Get yourself some 3" Winchester Longbeards XL for this spring. I did testing last year with these with the HD and the patterns are unbelievable.

https://youtu.be/hLwRYMV0K7E

I have been using Winchester longbeard shells for the last 2 Turkey seasons, they pattern better than any load I have ever used. I took a Turkey each year with them.

Joe, those parameters are typical for Model 12 Heavy Duck guns. Winchester put a lot of research effort into boring and chokes and was cautious (as compared with at least two other makers) in advertising 70 to 75% patterns for the Heavy Duck. That was with the 12 ga/3-inch 1-5/8 ounce load that essentially duplicated the heavy progressive 1-5/8 ounce loading in the "Short Ten".

i have a model 12 12 ga with 2 3/4inch chamber with a cutts choke on it really shoots good just don t like the looks of the cutts choke even though it does the job...charlie

Mod 12 HD
 

I owned a solid rib 1955 HD all original I bought 7-8 years ago. Really powdered two big gobblers with it one time who both decided they need to commit to sacrificing themselves one after the other. Also banged a few ducks it was a great long range bomber but due to shoulder problems I readily delt it in a trade last year for a pristine DHE 20 ga original 3" 30" bbls 1925 gun that is a joy to look at and shoot. Was made for a guy that belonged to a San Antonio gun club started in 1910 Blue Wing Hunt Club and is still in existence!!!! Frank thanks for comments on Model 12's I love my other 3 -20, 16 12 skt and 410 all solid ribs.

I would presume that the pre-WWII Model 12 Heavy Ducks through the early 1950s were bored for the 12-gauge 3-inch Magnum 1 5/8 ounce Super-X and Super-Speed loads that were brought out along with the Heavy Duck in 1935. I bought a very late Model 12 HD, in 1974, for duck hunting in Alaska, 1,9xx,xxx serial number range. The shells I had were Western compression formed Super-X, Mark 5, 1 5/8 ounce loads with #4 and #6 shot. I had plenty of time and shot five patterns with each shell and with the #6 my gun averaged 63% and with the #4 just shy of 70%. I've often wondered if these later Model 12 Heavy Ducks were bored for the 1 7/8 ounce 12-gauge 3-inch Magnums brought out in 1954? Since I came back to the lower 48 the next year the Model 12 HD has languished in the back corner of the safe and my old Super-Fox was usually gotten the nod when longer range work might be in order.