FYI
Heat treated CPM M4 sure is hard on fine grit belts.

M4 does darken with ferric chloride for those who are interested.

Chemistry for M4 is:
Carbon 1.42%
Manganese .30%
Sulpher .06%
Chromium 4.00%
Vanadium 4.00%
Molibdinum 5.25%
Tungsten 5.50%

Thanks
Tim

"The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
Albert Einstein

At Khe Sanh a sign read "For those who fight for it, life has a flavor the protected never knew".