[Springfield98]

I have seen and acquired several Mossberg 500's that look like true stainless steel. I know Mossberg offers a Marine Kote finish, but this is definitely not that. The surface is finished smooth. One of them has been filed a bit near the front of the magazine (why??) and it looks like the same white metal all the way through.

http://i123.photobucket.com/albums/o297/Springfield_98/gun/SS_Mossies.jpg

I called Mossberg about 10 years ago and the rep on the phone said Mossberg didn't make any stainless shottys -- too hard to machine. But these sure look like that.

Any knowledge or thoughts on this?

[Regolith]

IIRC Mossberg uses aluminum for their shotties. Whoever modified those probably just removed the black finish.

[Springfield98]

Thanks for your thoughts.
Definitely not refinished, or aluminum receiver.

[Regolith]

Have you tried the magnet test? Aluminum is non-magnetic, while steel and stainless steel is. If you put a magnet up to the shotgun receiver and it sticks, its steel of one variety or another. If it doesn't, its probably aluminum.

[Springfield98]

Yes, just tried that. Magnet is attracted to the receiver, barrel, mag tube, etc. But maybe it's attracted to the bolt within the receiver, not receiver itself. I'll take one apart (tomorrow) and let you know.

[Regolith]

I did some research and it turns out that Mossberg has made steel receivers. So if the magnet sticks to the receiver its possible someone just took it down to the steel surface and polished it up. It might also be possible that it has a nickel-steel finish. I don't know if Mossberg ever made any nickel-steel variants, and I'm not sure how easy it is to have a nickel-steel job done on a shotgun, so I don't know how probable that is.

[Springfield98]

Yeah, I was at a show today looking at the 590A1 mil-spec version. Dealer said the 590A1 has a steel receiver. Maybe these are simply nickel plated, although the serial numbers and other marks & stampings sure look crisp.

[mnrivrat]

Mossberg has never made a steel receivered 500 series gun . They have always been aluminum . Sorry to burst any bubbles but the rumors of the steel Mossberg receivers have never turned out to be true - I took the time last year, just in case, to contact the Mossberg company and they varified that ALL that they produce is the aluminum receiver gun.

I watched the basic process being done in Ohio 25 years ago or so. An aluminum billot is heated and then extruded in a large press to form the reciever - then machined to finish.

[Regolith]

Mossberg has never made a steel receivered 500 series gun . They have always been aluminum . Sorry to burst any bubbles but the rumors of the steel Mossberg receivers have never turned out to be true - I took the time last year, just in case, to contact the Mossberg company and they varified that ALL that they produce is the aluminum receiver gun.
Well, we'll see what happens when he does the magnet test without the internal bolt. that should reveal whether its aluminum or steel.

My source for that information wasn't necessarily the most reliable, so I can admit that I could be wrong.