I tried a lot of choke tubes in my 870 and my 11-87. Nothing seemed to help much until I recently tried a Jeb's Headhunter (.655 restriction). It improved the pattern with my 870 by over 50% at 35 yards. I highly recommend it. It's expensive ($110) but I refuse to pay $4 a pop for heavier than lead shot and the improved pattern using the Jeb's tube was with lead shot.