Very smooth operating pump gun. That's the first thing most people remark about it when handling one.
The double arm rail carrier is the main reason for that.
,,and when the critical areas along those arms get worn from heavy use, that's why the 31 won't feed correctly.
The bolt slide running along those rails moves the carrier up and down in a precise timing. When worn spots occur along the rails the carrier fails to move up or down as far or as quickly as needed and balky feeding occurs.
The shade tree fix is to gently squeeze the rails together. That lifts the shell up higher betw the 2 rail so it can be fed into the chamber easier.
But that only last a short time. Long enough for the seller to disappear out of sight of the new buyer.
The carrier can be rebuilt by welding if a suitible replacement can't be found. Many older parts are just as worn. A problem with any replacement parts for an older gun.
When buying one in person,, take a couple Dummy rounds along and feed them through the gun and make sure the gun functions OK. Should be NO balking at feeding the shell off the carrier and into the chamber.
If you have to double shuffle it to get the round to feed, the carrier is most likely getting worn. Shell stops should be positive and no double feeding out of the magazine.
The Mod 31 was made in several versions called 'Series' by the factory.
There's a 1931 Series,,1934,,1941.
Some parts are Series specific . Some are gauge specific.
There's also an Aluminum Alloy Lightweight version,,the Model 31L
Not to be confused with the Standard gun with a steel frame but fitted with an alloy trigger guard as an option (?) in later production.
Early trigger guards were steel.
I've replaced alloy trigger guards with steel ones for customers. As long as they are the same Series, the small parts exchange and a little fitting is necessary, the 'new' guard goes right back in.
The Model 31L Alloy frame guns have been known to develop cracks at the front of the frame where the bbl fits and also lower in front where the magazine tube is attached.
Nothing that seems to stop people from using the gun,,but the fine cracks in the alloy frame are there.
The 20 and 16ga Model 31L guns are some of the lightest at about 5.5+ lbs.
Vent ribs on Model 31's (and Model 10 and Model 11 shotguns) were made as one piece with the bbl itself. Not an added assembly. The posts and the rib are all machined out of the same billet of steel that the bbl itself is made from.
Prices?,,check the recent closed auctions for similar Model 31's. Pay close attention to wether the auctioned guns are original, have VRibs or plain bbls, cut bbls. polychokes added, cut butt stocks and pads added, all the normal stuff that can add or detract from value.
The bbl if Factory orig to the gun, should be ser# usually on the bottom near the breech. So that TD of the bbl would be necessary to see the #.
