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Hey Fellow 16ers,

Wondering if any of you Mod 12 owners have measured the bore diameter of your 16 ga. barrels. I picked up a nice '48 vintage mod 12 at a gunshow this past weekend. It has a 28" mod. barrel but the choke gauge showed a loose mod. and it measures the industry norm for skt.2 if the Mod 12 had a .667" bore. It may have been opened up a little which is just fine with me. I can always make a run to my gunsmith, was hoping you guys might save me the trip.

Thanks,

Dennis

Dennis
Are you just sticking a gauge in the choke end? To get the choke restriction you need to measure the bore and subtract the difference at the muzzle end. You measure back about 9". Bores will very even with the same model so you have to measure each one. Also as you said it could have been opened up some. Have you shot it for pattern ? Those bore gauges can be misleading. I have 16s with bores from .655 to .670 so you see what good would a bore guage made to an industry standard do with these differences. Measure then shoot it on paper and you'll know what you have. Smile

Joined: 20 Jan 2007 Posts: 40

The chart below is for the Model 21 but is the same for the Model 12. To determine if the gun has been opened up you need to measure the choke diameter.

http://members.tripod.com/bluepike/Model21/goldmodel21choke.htm

Joined: 16 Mar 2007 Posts: 6 Location: Upstate NY

Yea you got to measure them. I have a mod barrel on mine and it's stamped mod but it measeures .672 Bore and .652 choke. I think it's an imp. mod that got stamped wrong. Mines from 1928. Enjoy it, it's the sweetest shooting gun I've ever owned.

Member Joined: 26 Apr 2005 Posts: 743

According to Jack O'Connor's "Shotgun Book"--which was written back when Winchester was still making the Model 12--standard Winchester bore diameter for the 16 was .664. Standard choke constrictions in the 16ga were 7 thou for IC, 16 for mod, 31 for full. Remington's choke constrictions were almost exactly the same, but their standard bore diameter was 9 thou larger--which is why you can get misleading readings from those "slip in" choke gauges, if you don't also measure the bore diameter. And Browning had a similar 16ga bore diameter to Winchester, but their choke constrictions were much tighter. 16 thou in a Browning 16 was IC!

Between the replys to this thread and a couple PM's I have answers that range from .663" to .672". I was hoping the Mod 12's were more consistant with their bore sizes. The choke on this gun measures .657" which puts it in the middle of the Mod range per J.B.'s chart but would make it an I/C per Larry/Jack O'Conner and a PM from Drew.

I will pay my gunsmith a visit, get it measured and report back with the results.

Thanks again,

Dennis

Member Joined: 18 Nov 2005 Posts: 398 Location: S Fl

My database includes a 1940 M12, bore is .666 with 004 choke. Barrel is marked IC.

Pete

Joined: 27 Apr 2005 Posts: 380 Location: Northeast Ohio

My 1959 gun measures .669 at the bore with .009 constriction at the choke. It is factory original. My close friend has an earlier one also original, also with .009. Both are marked modified. I spoke with Winchester about my gun and was advised that my measurements were well within manufacturing tolerences back when it was made and were by no means unusual. That being said, according to the charts and what other's guns measure, it seems closer to skeet 2 or a tight IC or very light modified.

I would add that it seems to be about perfect for my needs which are mostly low gun skeet and dove hunting. I would hesitate to change it in any way. I'm a swing through shooter and tend to ride my skeet birds to about 30 yards on the middle stations anyway, and I don't feel over- choked for the closer ones. It appears to give even breaks over a wide range of distances from very close to forty yards. I am going to pattern it this summer and will report the results. Sure has killed some distant doves.

I've toyed with the idea of installing tubes but I don't think I'll bother as this works so well all around.

The only way for you to really know what you have is to measure bore and choke. And of course, we should all pattern for optimum effiency and confidence. My problem is laziness and trouble with mundane tasks!

Good luck.

Member Joined: 31 Aug 2005 Posts: 1257 Location: Nebraska

My M12 16 Mod measures 009". So does my 12ga M12 Mod. My WS2 barrel in 12 ga measures .014". That bears out somewhat, a listing out there shows that at one time at least, Winchester bored out their WS2 to the same as their Mod constrictions. Just named it different.

My 16ga Win barrel marked Imp Mod measures just under .015" . That's not quite up to specs as listed in some charts, but when I had Andy's Gun Shop check it out they thought it was original. It can pattern 65% with some shells, so it can make Imp Mod. Don't count on that from some shells.

You have to pattern.

kgb

After giving the barrel a real good cleaning I paid my gunsmith a visit. He came up with a .671" bore and a .661" choke diameter. So this barrel correlates exactly with J.B's chart. I am happy that the choke is on the light side of Mod. Most charts would call .010" restriction Skt II or L/Mod.

After arriving home I checked the choke with my dial calipers and I also measured it at .661". I guess my original reading of .657" must have been due to some light plastic fouling although the barrel looked clean.

Will have to see how it patterns someday.

Thanks again for the help,

Dennis