Okay got home , and properly measured out the count its actually 240 ! at 40yds. out of my 23inch sp10 , federal 2oz 1300 fps #7 , phenomenal tight pattern, there was a slight side breeze , first and only test shot , I'm sure if I kept on going I could get a higher score
...pick yourself up some fed#7 for CHEAP before it's gone forever
William made some of these many years ago but had lost the data to make one in a hardware crash and was unable to make one ...I sent him my barrel and he redid the program to make some more ....get on this while you can , best shooting 10 ga choke I've ever seen ,he is a amazing gunsmith and choke builder ...the choke measures in at .685 with straight lands and wad stops on the internals.
Thanks for looking
Shannon