I use 4mm drill blanks I pick up from McMaster-Carr.
http://www.mcmaster.com/#2900a278/=1j9spj
cut them to 66mm with a HD Cutoff wheel and you should be all set. I've never had a drill blank bend it buggy or truggy. Just make sure you get USA HSS you can get Chinese steel but they will be worse than the stock pins.