ISM62,
The brake is new and needs to be indexed with your action. The bore diameter is smaller than .30 calliber and will need to be .020 over your bore diameter. I believe this is standard for all Painkiller brakes. Yes, the brake has 3 ports on top only. I'm cuurently traveling and don't have the brake in hand to measure the shank. However, if you search for the painkiller slim (medium) version you wil see a picture of one installed on a Sendero. If I remember correctly, Kirby has the dimensions listed for the brake as well. Again, this brake in new and has never been installed. Thanks, Jimmy