I have a Remington 870 Wingmaster that has a 2 3/4" only barrel that came with the shotgun. A friend of mine has an 870 Magnum with a 2 3/4 or 3" magnum barrel. Looking at both of the 870 receivers, I can find no differences other than his having "magnum" etched in. If I put a 3" barrel on my Wingmaster, 3" shells cycle with no problem. Can I safely shoot 3" mags in my 870 Wingmaster with a 3" barrel installed?

TIA

The difference with a 2 3/4" receiver is that the ejector is set forward 1/4" forward than a 3" receiver. If you put a 3' barrel on the standard receiver you will be able to cylce loaded 3" shell and shoot them in a 3" barrel but you will not be able to eject the spent casings since the 3" shell is now 3" long. A loaded 3" shell is actually 2 3/4", and a loaded 2 3/4" shell is actually 2 1/2" long. It is possible that you have a 3' receiver and don't know it, years ago Remington would only sell Magnum receivers that are marked on the side, that was the only way to get a 3" barrel. They would only sell barrels in 2 3/4 ' chambers. Thanks to competion with manufacturers like maossberg and winchester who wanted to gain market share that remington started making all their receivers to handle 3" shells same reason that they came with choke tubes.
The only way you can tell is simply chamber a fired 3" shell and work the action if it easily and smartly ejects the shell you probably have the mag receiver.

raamw is correct about the difference between the 2.75" and 3" guns for function. All magnum receivers have a M in the serial number. You also can change the ejector and spring on your 2.75" receiver over to the 3" setup.

reamw

Thanks for a very informative post. I am ashamed to admit that I have been shooting shotguns for over 50 years and never knew that a 2 3/4" shell was actually 2 1/2" long before firing.

I guess this is on a par with the fact that until about 10 years ago I never knew that the diameter of the pattern of a 12 ga. and a 20 ga. were approximately the same at the same distance. (Being an exclusively 12 ga. shooter, I just "assumed" it as a fact that a 12 ga. had a larger pattern)

I'm getting smarter as I get older.