Shot my x4 with the.570 briley that comes with the cantilever barrel and my .581 hevi choke. At 30 they both seemed pretty similar, with the briley being slightly tighter. At 40 yds though the briley seemed to have opened up more and the hevi kept a better core with a nice even pattern. I have to shoot more but from 1 shot at 40 with each choke shooting apex ninja #8.5's 3" I had 225 in 10" with the briley and 298 with the hevi choke.