Regardless of load/barrel/gun, I have consistently achieved my best results with Sumtoy Custom Chokes. William is on this site, and he is a good dude. Look him up...his stuff won't disappoint. I have an 870 with a 23" barrel, running his .660 and Magblends...it is nasty what comes out of it. Anything under 20-25 yards, and you better be dead-on, though. It also gave me fantastic patterns with longboard 5s and 6s.