The Ithaca model 37 uses receivers scaled for the 16 gauge, and are great pump guns.
I bought a new made in Ohio model 37 in 16 ga. Not sure of frame size, but it was very heavy. I sold it.
My first shotgun was an "original" Model 37 16 gauge, a late '40's gun. It handled and functioned like a dream. Unfortunately, a duck hunting mishap consigned it to the bottom of the St. Lawrence river. If I understand correctly, the "new" Ithaca 37's, when they made a 16 gauge (which they don't seem to list anymore) were on their 12 gauge frame. To add insult to injury, they make all their 12 and 20 gauge guns with a receiver for 3" cartridges. To my mind, that's a complete ruination of the Model 37. My current 16 gauge guns are a Fox Sterlingworth and a Merkel 1620. I also have 20 gauge barrels for the 1620 and use those to shoot clays, generally, and the 16 gauge barrels when bird hunting.
