The MCR Power Adaptor will make life much simpler for you while you're uniforming your meplats with the MCR Meplat Uniforming Tool. It consists of a 1" diameter 303 stainless body with a 1/4" hex shank for being held in a powered driver. The Power Adaptor also takes place of the knurled stop. So, in essence, you have a new stop and a power adaptor built into one unit. Endmill is held in the same fashion as with the knurled stop and can be used for any caliber from .224 - .338 .