Bought this choke from a member here to use exclusively with Federal Heavyweight shells size 7 out of my Remington compact. Must be the flight control wad, but it won't pattern for me. Hence I'm moving it. Has been fired twice so mint as they say. Choke states it is .565, but it isn't based on my digital caliper. My Caliper says it is .575. I believe it will shoot fine with TSS, but since I have 12 boxes of Heavyweight I have no desire to go that route. TYD $50 . Price Drop. $40 to your door.