Both of my Invector Plus guns pattern the "Old Green" Remingtons and the Hevi-13, 5's, 6's,& 7's best w/ the IC .670. However, both guns pattern best w/ the IC .675 w/ HeavyBlends. I killed a bunch of gobblers w/ the "Old" Remingtons, 5's & 6's and got the best patterns w/ the higher payload/lower velocity shells in both the 3" and 3 1/2" configuration. I get best patterns w/ an IC .660 in my straight Invector shotguns w/ both the "old" Remingtons and the Hevi-13 loads, not enough difference w/ MagBlends from a .660-.665 or .670 to justify changing chokes.