It takes the same stock as the other Mossberg guns, it's just a matter of choosing wood or synthetic, plain finish or painted, and some like the 20ga or 410 are shorter. You can buy from Mossberg directly, some gun sites, plus there are aftermarket stocks available too. Ebay has both new and used, many people buy a new wood gun, then buy a synthetic trim for it and sell the wood on ebay. You can paint a wood one black if you're just after the color. The syn is nicer looking (to most), slightly lighter and has more space inside for storing goodies like survival stuff or tools etc.
Mossberg 500.
You will need to provide a DETAILED descripton of ALL markings, gauge, barrel length, forearm, butt stock, etc..
In front of the butt stock .
You will have to replace the butt stock.
The butt of a rifle or shotgun- the part that goes against your shoulder.
I have one for sale. Message me @ garym6@cox.net
Remove buttplate. Use a socket extension and rachet to unscrew the stock bolt (it's in that hole in the center of the butt)
There are two small holes in the butt pad of the stock. Lubricate a Phillips head screwdriver into the holes and remove the butt pad. Using a long flathead screwdriver remove the screw in the center of the stock. To add new stock simply reverse.
I have one for sell in very good condition.
The butt plate screws (2) at the end of the stock must first be removed. You will need a long shank flat tip screwdriver to remove the screw at the bottom of the center hole in the stock butt. Reverse to reassemble.
Stocks for the 1200, 1400, 1500 should interchange. Nummrich (gunpartscorp.com) has synthetic stocks in stock.
Remove the butt plate. There will be a hole. There should be a slotted screw at the bottom of the hole. Use a long screwdriver and be careful to not damage the stock.