I'm not 100% SURE, but I think the Mossberg 590A1 steel guard will fit the 500.
The problem: Mossberg probably won't sell the guard unless THEY fit it, and the guard will likely be expensive.
Contact them and ask:
http://www.mossberg.com/
There are only two steel guard assemblies I know of for the Remington 870.
One is the guard from the Chinese "clones" of the 870 made by Norinco, and sold under names like Brolin, Interstate Arms, Hawk, and others.
The only way I know of to get one is to buy an entire gun.
The other steel guard is/was a special steel assembly made for slug gun shooters who wanted a rifle-type adjustable trigger assembly.
It is/was available from:
Allen Timney Gunsmith
13524 Edgefield Str.
Cerritios, CA 90703
310-865-0181.
Also from:
Hastings Barrels
4th East Court P.O. Box 224
Clay Center, KS 67432
913-632-2184
The standard Remington Wingmaster and Police aluminum guard will fit the Express, and these are fairly easy to find on Ebay and some parts houses.
