"1000 miles from my 870" That sounds like a great country song.
I came across a Straight Rifled tube last year. I have been shooting Super x 3" #5 out of 21 inch barrel 870. Been testing a few different chokes. Now my distance is only 30 yards. Chokes tested were, Ventilator, Kick's .655, Jellyhead, Indian Creek, Rem. extra full, and the Straight Rifled. The Straight Rifled produced the best patterns for me. Although, as you all know, at 30 yards they will all work.