Belt life expectancy for grinding M4?

[Whoever Wherever]

Anyone know this for 2 x 72? I've heard from several places that this stuff is a bear to grind. I got to try out a blade in it though and love it. Anyone done anything with it? Wondering just how bad it eats belts up?

 

[Phillip Patton]

The life expectancy for belts is very short with M4. I've only ground 4 blades from it, and when grinding it annealed, it was like grinding hardened O1. But I think it's worth it. M4 has some very desirable properties...
Grinding with the machine is a lot easier than hand finishing. All the blades I've done with M4 had a machine finish because I haven't figured out how to do it by hand.