milling hard rifle actions

[elc]

trying to mill the top of 40x actions for scope rail and then rotate to 15 degrees to mill out left side to make dual loading port--problem these actions are very hard on surface the depth of hard varies from action to action--on the left cut it is hard on inside and outside with machinable core--i am using a tormach with 4th axis and made a mandrel to hold work--am wearing out carbide mills at a rapid rate and chipping mills even faster--when i try cutting the left side using the side of the mill with a lot of pressure and get through the hard surface the sprial grabs the work and pulls the mill adaptor from the r8 collet in the headstock and into my mandrel--am using koolmist and air--would a left spiral mill work putting pressure up?--carbide burr? or any suggestions

[neilw20]

Mount a small CBN wheel and grind it. Slightly slow, but really easy.
On hard stuff don't run carbide mills too fast. Sometimes air instead of coolant is better, as the hot chips harden as you produce them.
I have machined grooves in ball races using tipped tools intended for chilled cast iron. Really slow feed and speed here too.