Sounds like what you might have is a "Kit Gun".
You're right. They made 22s on the M frame, the I frame was a 32, the K frame a 38 and the N frame the 44.
But they also took the I frame and put a 22 on it, figgering that the heavier frame would make the gun easier to shoot accurately. It was originally called the 22/32 (that's .22 on a .32 frame) Kit Gun. Later, when they came up with model numbers, it became the model 34, and then when they started making stainless guns it was the model 63.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
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Beware the Evil Bullet Fairies.