AYA #2 16 ga are on a 16 ga frame, slightly larger action than a 20 ga and much smaller than a 12 ga. We have a couple, as well as a 20 ga. Sold the 12 ga, as I like the 16 ga much better.
As per 870s....the old ones were small frame (family had 2), and I believe a run of new were on the 12 ga, although i never had one and don't want one! Don't know years or serial #s.
I've owned a few M12 16 ga and they indeed were all on the common frame shared by the 20 ga and 28 ga....and a whole lot smaller than the 12 ga frame. The early 2-9/16" gun would function perfectly with black Remington "2-3/4" cases, but not with Winchester or Federal factory ammo as once the cartridge was fired it would not clear the short ejection port. Obviously the Remington cases were shorter. Nice guns!
