I've been searching Midway USA, CheaperThanDirt, etc., for a tactical butt-stock and fore-stock setup for my wife's Mossberg 500 20-gauge, but am having a hard time getting clarity on exactly what will and won't fit. Some are listed as 12/20 gauge, others just say 12. Overall, I could use some recommendations or help here. The gun is already a pistol-grip gun, but has a black wooden ribbed forestock. I'd like to use a 6-position tactical butt-stock and basically "militarize" the whole thing. Any recommendations, and better yet, part numbers/links, would be greatly appreciated. Thanks!