I have an 870 with a 660 sumtoy and the gun likes 5's in lead. I've shorter XX's, HV's, grey box winchesters and the thugs. The gun Shot 5'a in all those loads better than it did 6's. I'm gonna be huntin with the turkey thug 5's. I'm averaging 110 with the thug 5's. I was averaging around 100 with the HV 5's. I don't think u can go wrong with a sumtoy choke. Great guy and great choke. One oft favorite things about the choke is how even the pattern is. It's a helluva choke.