Is there a good website out there that I can purchase tactical parts for my 870 limited edition (Walmart) 20 gauge shotgun?
Only thing I can find is for 12 gauge shotguns.
Thanks,
Brett
Wilson Combat has some parts for 20 ga. 870s. A year or so ago, I used one of their mag extensions (formerly Scattergun Technologies) for a 20 ga. 870 Mag youth gun I tweaked for home defense. The mag extension comes with spring and follower. I also found an 18" (or was it 18.5?) plain cylinder barrel for the project.
PC
Second that. Check with Wilsons. Several years ago I had them build a pair of 20ga tactical shotguns. One 870 and one 1100.
They are very neat little shotguns.
Thanks, I’ll look into Wilson. I’d rather convert than purchase a whole new shotgun! 
Again, thanks for the feedback
Another nod for Wilson’s. I have one of their 20ga 870s and it’s slicker than snot on a doorknob.
Mesa Tactical makes 20 ga sidesaddles for the 870.