I already have 2 turkey chokes for my 870 super mag. One is the factory remington super full choke and the other is a turglo gobble stopper extream ported. Both are .665. I see primos offers 2 jelly heads one in .665 and one it .660. what would be the advantage of the .660? I usually shoot 5 winchesters or remingons.

I have the same gun and with the .665 and the Hevi13 #6's... I'm getting good patterns out to 45 yards...