Good luck with your project. It's way above my pay grade. I bought a 16 ga 870 that looked like someone had removed a polychoke or something similar from the barrel. The rest of the gun was solid and real cheap so I brought it home. I sent the barrel to Colonial to have them make it screw-in ready, rather than have it sleeved. Back then (15 years ago) it was about $125 and they gave you a tube. It came out great and I bought a turkey tube for it too. The bad part was you had to use a ramp for the bead. Had a "gunsmith" do one for me that fell off after a few years. I sent it to Shotgun barrels and stocks and had them install a vent rib. I took it out grouse hunting last weekend, I got one shot and connected. Weighs 6lb 10oz and isn't bad to carry.
