I have an Ithaca 37 that I love. I own other shotguns that I shoot more but do not own a tactical/home defense shotgun. So I am kicking arounnd the idea of turning my 37 into a defense shotgun I.E 20 inch barrel and high cap. mag. tube. Nummrich has the barrel but not the mag tube. So is there a better source for the parts I am looking for? Should I just shine it and buy a mossberg that's already set up for home defense? Thanks, in advance, Damian