Identification, Remington 870 chamber/gauge?

[mark-hunter]

So, the question for Remington 870.
Barrels stamped: ammo 2-3/4'' and 3'' for magnum receivers, 2-3/4'' for "all other".

How to identify then, which receiver it is, and what ammo to use?

Trial and error method, if it doesnt feed 3'', then it is 2-3/4'', or there is some other way?

 

[BeeMaa]

Two components.

The receiver needs to be long enough to cycle the desired cartridge. For most 870’s marked “magnum” this means 3” and they will cycle 2 3/4” and 3” (magnum) shells.

The barrel needs to be proofed for the load. The barrel in your picture is capable of shooting 2 3/4” and 3” shells…as long as it’s attached to a receiver capable of 3” shells.

The confusion comes from people swapping stuff around almost constantly on such a ubiquitous platform. This necessitated the Remington lawyers to put stipulations on the barrel. A litigious society and lack of common sense would be contributing factors.

One also needs to remember that the 3.5” shell didn’t exist until the late 1980’s so for a very long time, 3” shells were considered a magnum load.

 

[62flint]

The magnum recievers (3inch) had a M as the last digit of the serial number if memory serves me correct. Also the ejector on the 2 3/4 recievers is to far forward to relialbly eject the 3 inch shell. The 3-1/2 inch reciver the bolt has a shroud to allow it to collapse and move reward further making room for the longer shell to eject.
So if your reciever is desingtated as a "magnum" Feed it 3inch shells to your hearts content