I have one that belonged to my Dad. Its a 31L with aluminum receiver. Very light and kicks like an angry mule. I killed my first 3 deer with it before I got a rifle plus a couple of ducks, some doves, and a squirrel or two when I was a kid. I used to shoot it all the time way back in the day. It has a very smooth action.
Mine is not checkered but has ribs on the forend. I think they quit making them in the 1950's sometime and I assume they were replaced by the 870.
The Sportsman 48 was the lead-up to the 870. The 31 is not even close to the same gun. I think the swap to the 48 and end of the 31 was a little earlier and they made the 48 and the 870 together for quite a long time, but the 48 was first. 48 and 870 barrels are interchangeable, too.
