I would do it for you, but I don't have a McR20
But you could get a Step drill bit and do it your self, the reward will be greater in the end, plus it is really easy, and you could do it again. :twothumbs
D.I.Y Lumafist,
I would not use any powertools, you might overdo it a bit
Use a hand reamer and some diamond files .... do it all by hand, your less likely to make any mistakes.