Hello to all, I am new, and my introduction is entered in "General Discussion". I have a couple of questions on backboring: I have an 870 Rem. barrel (3") that has been Briley choked, (screw in) and the forcing cone has been lengthened to 2 1/4". This barrel has been shot a lot, and is shot scarred just beyond the cone. I tried to polish it with Flitz but the marks are still there. I would like to have this barrel backbored and polished, but am uncertain this can be done with it having a screw choke. Any comments? Also, if this can be done, approximate price?