All early ones (pre early 1970's I think) were on a 12 ga frame. The lighter feeling was the smaller barrels on the 20 and 16. I have a first year 20 ga and a first year 12 ga. Everything the same other than barrel. I think the early 20 ga guns are much smoother and better built. But you do have to look a lot harder to find replacement barrels since they are not interchangeable with the later 20 ga frame ones.
