Fully stripped and cleaned M 31 Remington 16 G few months ago, very good UTube Video on how to do it. They can be a puzzle.

I use 3 Remington pumps, 12 870 16 & 20 M 31's to make emptys at the skeet range from factory loads for my SxS guns. Not being competitive outfits I only shoot doubles low gun. Might be comming out of your shoulder just a bit pumping and back on the bird is a better way to shoot. They get a lot of attention on the Skeet field. Nice old guns.

Boats