I think it's not the pin which is worn out but the cva-bone. I gets a sharp edge where the pin pushes against the bone and cuts the pin if the edge gets too sharp. I noticed that the right CVA was a lot more worn out than the left and the sharp edge is only at one side of the bone, so im pretty sure it's the accelarating which damages the cva and not the breaking. Wish i could make a pic, but my fucking camera doesnt work :/