I tried a 12/18 -7mm hooker in my mag pump. It was a huge letdown. First it was cutback enough that the hub rubbed the pump. Finaly found a washer to put behind it and ran it only to find it slips like a mad. It was pitched for my setup and its not even close. Getting them on the phone is about as bad. May have to wait until winter for them to answer their phone again.