Winchester Model 21 Frame Size

[Tom Jay]

Is the 16 gauge Win Model 21 frame size unique to its gauge or is it built on a 20 gauge or 12 gauge frame? Thanks.

[James L. Martin]

Winchester Model 21 started with 2 different size frame forgings. One for 12ga and the other for 16ga, 20ga, 28ga and 410. Then they were machined for each gauge and weither they had a solid rib or vent. Bottom line 16ga and 20ga are very close in size.

[Tom Jay]

Is it possible to have 16 gauge barrels fitted to a 20 gauge gun?

[James L. Martin]

The striker holes on 16ga are 1.08 and on a 20ga it's 1.02. Don't know if that close enough or not. A gunsmith needs to chime in.

[Tom Jay]

Probably not worth messing with. Thanks.

[David Lien]

The striker holes on 16ga are 1.08 and on a 20ga it's 1.02. Don't know if that close enough or not. A gunsmith needs to chime in.

Tom and James
At the last winters Vegas gun Show I asked Tony G. that very question. His reply was that his firm did not do this. I had a set of 30 In. 20 gauge factory 3 " chambered barrels dated 1953 that were orphaned, and I was lookin to buy a gun to put them on. I asked tony if a 16 Gauge gun would work and he was quite clear that a 16 gauge gun would not do what I wanted to do. Lots of 20 gauge guns at the show, and i had little trouble finding a gun that they went on. David

[Phillip Carr]

Im guessing it would be a possible for an experienced gunsmith. I just had a set of 410 and 28 ejector barrels barrels fit to my 20 gauge by Bill Schwarz.
Of course the 20,28,and 410 all used the same frame. I would think you could fit the 16’s to a 20 gauge as you could strike the barrels to contour the bolsters.
Plenty of other guns have barrels fit up after deivery to make 2 gauge sets. Good possibility Winchester 21 is the same.

[John Dallas]

By mistake, I snapped a set of 20 gauge barrels on a 12 gauge frame (Don't ask) Mr grouse was very happy when I pulled the trigger and nothing happened

[Bill Murphy]

Phil, "The same as what?"

[Phillip Carr]

Bill, sorry for the confusion. The same as a 10 gauge Parker that had a set of 12 gauge barrels that were fit to the gun. 16 gauge after market barrels that are fit up to 20 gauges I believe. although possibly the barrels may have been produced to meet the firing pin measurement of a 20, not sure. A LC Smith 20 Gauge with a set of 28 gauge barrels I had fit up by buck Hamlin for my Crown grade 20.
My 10 gauge worked just fine with the 12 barrels but the couture was not perfect. The firing pins stuck the 12 gauge shells slightly off center but worked perfect.

There was actually 3 Frame sizes for the 21's but surprisingly very little difference between the frame's overall dimension's.

I can understand how a 12 frame would not work with a 20 gauge set of barrels as the distance between the striker holes on a 12 gauge is 1.14 and a 20 gauge is 1.02. The 16 gauge is much closer I believe 1.08.