Deer/Turkey/HD gun

Most of those short barrels aren't threaded for chokes. Could you use your current barrel for turkey (i.e. is it a Full choke or threaded for tubes)? Otherwise, it sounds good.

"Can a gunsmith thread a 20" IC barrel for a choke? or does that not work that way?"

Yes, he can. I have an 870 with an 18" barrel modified for screw-in chokes. I also have the Wilson Combat ghost ring sights installed. I use mine for just what you've described - deer, turkey, and defense. It fills all three of these roles very nicely!

The 870 sitting muzzle down in the corner near me started life as an 870HD (Home Defense) version, with an 18" bead sight CYL bore barrel. Its original owner had MMC ghost ring sights installed on it, plus some other stuff. I bought it from him when he got hurt in a helicopter training accident (he was in the Army) and he needed to shoot a semiauto shotgun as he could no longer run a pumpgun.

I had Colonial Arms install RemChoke tubes in the barrel, and lengthen the forcing cone. I put on a shortened Speedfeed II 'solid' synthetic stock with a KeckEez pad and a 7" LE type forearm.

As long as the barrel walls in your barrel are thick enough, any one of several companies can shorten it and put in choke tubes for you. RemChokes take a little more 'meat' in the barrel, but there are several kinds of tubes that will go in thin-wall barrels successfully. Find a good company to do the work, and let them tell you what is best for your situation.

But what you are proposing sounds nigh onto ideal to me for the purposes you list. I'd go with an 18" barrel and MMC sights, the rear sight ring is thinner and protected by steel wings that are part of the sight assembly. Get their solder-on type front blade and have that silver soldered on and you'll have what is IMHO the best sights available for a working shotgun.

Good luck with it!

lpl/nc

Think about having a Polychoke put on the barrel. I had all my shotguns fitted with them and I am very happy. With a 20" barrel, you can't afford for a gunsmith to mess it up. You don't have much room to play with legal wise. With a Polychoke, you can add a couple of inches. My Browning has a 20" barrel and it has put a lot of deer and turkey in the freezer. Most of my barrels were cut down so that with the polychoke the overall length is 24". The installer cut them down and made the installation. Costed a little over $125.00 but well worth it. Those things really pattern like you dial them in. just a twist of the wrist as they say and you don't have to fumble with screw in chokes.