please do not think the stated size of the reamer should equal the diameter of the blank you are trying to work with. I bought the medium size reamer based on the stated butt diameter of the blank I also purchased, and it was immediately obvious that I was ruining the grip I was trying to fit. Expensive lesson learned... seems like a very high quality tool, just beware that you should go WAY smaller than you think. I ended up buying a new grip and the smallest size tape reamer (not "extreme reamer") to fit my newest build. I will keep it instead of going thru the trouble of returning it, who knows I may use it some time in the future.