This choke patterns awful I got the choke put it on my browning BPS 10 gauge and I was using Winchester double X shells (copper plated lead) and the velocity of the shell is around 1300 so I was not going over what was recommended and the first shots I decided to stay close at 17 yards and it shot great perfect pattern then I decided to go to 25 yards then I was concerned because the pattern was about 2 feet around then I decided to go to 35 yards then the pattern was barley even on the target, but turkey season was in a few days so I decided screw it ill use it anyways and I shot a turkey at 50 yards it dropped dead... I was shocked, but I was looking at the spur and I noticed that one of the BBs hit him in the leg. so I decided to look further to see how the choke actually performed and sure enough the grouping got so big that only a few BBs even hit the bird I am still amazed that the bird even died. NOT WORTH THE PRICE. do not make the mistake that I did go with a non ported traditional choke