I have a 12 gauge 1953 Remington 870 Wingmaster Magnum shotgun. There is about a 4-5 inch heavy, solid metal bar that is the magazine plug. It is held in place with a single screw through the magazine tube. It is very well made and nicely blued, matching the guns original finish perfectly. The standard 870 barrel retaining cap covers and hides the screw.

A gunsmith recently told me that he thinks that is an aftermarket modification and not factory; he says they did it for balance.

Does anyone know if this is factory or a modification?

If a modification which spring steel/friction cap should I look for to bring the gun back to original?

This is a very nice 870 wingmaster with tootsie roll pump and highly figured oil finished stock (factory finish). It has a 30 inch Full choke plain barrel on it. I also have a much later 28 inch lightweight 12 gauge VR/RC barrel for upland bird hunting.

Sounds like a trap gun to me. I have only ever seen them on trap grade guns and they are a factory offering to add weight to the gun. I bought NIB 1969 870TC that had that in the unopened box so Im sure its a factory item. Does your gun say 870TB, 870TC or even 870SC on the receiver?

I've seen it on field grade guns meant for waterfowl hunting. They all had 30" full choke barrels. The steel plug promotes a smooth swing and the added weight reduces recoil from magnum loads.

Mine says MAGNUM Wingmaster.

The ejection port is 2.950" and I believe it to be factory original.

The magazine plug is 4.50" x .910"

I do have the original barrel and here are some pics.

looks like OE to me. nice gun! I have a 12 ga in the Magnum receiver, and a LW 20 ga Magnum, like them a lot

Further research indicates this is a factory item, the Vari-weight Plug, 12 oz. blued steel. Offered from 1950 until at least 1972, which is the latest Gun Digest I have with it listed. Perhaps Gun Digest never updated and deleted the Vari-weight plug.

OE for sure.

3" Winchester Model 12 Heavy Duck guns had a similiar setup in the butt stock.

I have never had the privilege to handle one, seems like it would make them real butt heavy

I have one and it balances really nicely , they were supposed to be a combination of taming recoil from the relatively new 3" mag shells and to improve balance with the 30-32" barrels on the heavy duck model 12s.

This is my understanding/experience as well.

Hey!! welcome to the 'fire longarm

Thank you! Very pleased to be here

The barrel on the Model 12 Heavy Duck was thicker than the standard gun and heavier. The lead weight in the stock helped balance the gun.