.650 out of a 20 inch barrel winchester 1300. Modern day powders burn far too fast so the barrel is not an issue IMO. Forcing cone, chokes and the loadall matter. Although having said that the 1300 26 inch that patterned with me tried it and got the same results with X-tended.

The Hevi-13 was not good at 30 yds much less 40. I had bought 2 boxes having used Hevi-13 with my Briley choke very effectivley (.680)As I said the X-tended did what you see above so it was no contest. That by the way improved things from 110-120 average with the Briley Hevi-13 combo. I was getting 150-160 with the Indian Creek and X-tended.

Great chokes with this set up out of my gun, no question. I have got a definite 40 yard turkey rolling gun.