I have a 12ga. M1 Benelli with a 26" barrel. I have tried the Jellyhead .655, ICC .665 and on Clark's advice the SSX. I tested the SSX this past weekend and it performed best with Hevi Magblend 5,6,7. I got a high of 189 in 10" at 40 yds. This is the best my gun has done with any combination of choke and shell. None of the chokes I tried put more than 150 in 10" with Hevi 6. The ICC and SSX did about the same with the 6's. Both threw nice, even patterns but not high center numbers. I think I may have a bad batch of Hevi 6's and I was not able to get any new ones this year so I am going with Magblend when our season opens in two weeks.
Just for fun I also shot a Hevi 5 and got 115 at 40. I also tried a Super x Win. copperplated #4 1 7/8 oz of shot and got 91 in the 10" ring. I use the #4s for hogs that I encounter while turkey hunting. They will take down most hogs within 30yds. You need to be a bit closer for the big ones but they are lethal on them too if you can get within about 20yds.
As an FYI, my POI changed with the Jellyhead. It was off about a foot at 40yds. In addition the ICC and SSX outperformed the Jellyhead in my gun with every shell I have tried in the past. I know it works well for some but it did not do well in my M1.
Good luck.
