Good Point John. The difference between 20 gauge and 12 gauge firing pin centers is waaay more than 1/32".

I wonder what the firing pin spacing is on a WIN-21 12-gauge frame and what it is on a WIN-21 20-gauge frame... what the difference is?



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Dean. Am at my cabin. Will be home tomorrow and will measure. I don't remember seeing those measurements in Schwing's M21 book.

A 1/32" may not seem like much when looking at the primer head, but the primer's anvil is quite pointed, and I think you're asking for misfires.

If the pin were as pointed as the anvil I would agree, but the ‘firing pin’ is rounded.





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Pointed or rounded, if it doesn’t strike the top of the anvil, you’ll risk a misfire.

I get that Edgar. What I'm doing is playing the devil's advocate here in this case.
If I had a 1-frame hammerless and an orphan set of 1 1/2-frame barrels I would attempt it myself. Like I said previously, there is no danger in doing it and I would really like to know.
Incidentally, I do have a 1-frame GH 12 so if anyone has a loose set of 1 1/2-frame barrels I would entertain procuring them for the stated purpose.





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Dean I just measured my 12ga & 20ga model 21 .12 was 1.145 and 20 was 1.020 for a difference of .125 or 1/8 inch.

Now that’s a lot.

No wonder it didn’t fire. :cool:





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My ham-fisted measurements Showed 1" 4/32 for the 12, and 1" 1/32 for the 20.

I'm with Brian and Edgar, the only time when 1/32" is negligible is when your cutting a 2 by 4 for an outhouse.