I dont know about the drilling issues, but the part about leaving rubber marks on the approach makes no sense. Rubber balls were very popular and used for decades in all centers. If they were causing approach problems they wouldnt have been practical. The other thing that doesnt make sense is these are HARD rubber. In order for them to hook even less than plastic ( which I found further info on the web confirming that), the rubber would have to be a very hard rubber compound which doesnt sound to me like it would be leaving streak marks on lanes or approaches. Like I said, Im no expert on such matters, we shall see. It just doesnt make any logical sense that any ball harder than plastic, which is already very hard, is going to be shedding particles/leaving any visible marks in use. The other issue is the lane oiling. Even if they were soft enough to leave a skid mark on a dry lane, sliding on oil at release point would lessen that considerably wouldnt it?
Hooker - Brunswick DANGER ZONE PRO HPH 15.5#
Spares - Japanese Ebonite HARD RUBBER 15.5#