Quoted from PinMonk:It's been over a year since I did it, but if I remember right it was because I didn't have the correct size on hand, so I put it around the third post to take up the slack. That's the first and only rubber that broke on GnR so far. Broke within a month. Caught me off guard. That's why it's white rubber instead of the stock translucent.
Amazing. Both of my slings broke within 50 plays! You've got good mojo.