There were two different models of Rem 700's. The ML and the MLS.

Per Remington:

The 700 ML instruction manual states that the maximum charge should be held to 120 grains of black powder or Pyrodex in .50 caliber rifles and 90 grains in .45 caliber rifles.

The 700 MLS Magnum earns its "Magnum" nomenclature by being rated for up to 150 grain charges of either black powder or Pyrodex.

So Actually the ML I sold will shoot 120gr of Powder or Pyrodex. I used loose powder initially and switched to 100gr of Pyrodex pellets the last several years of using it and it shot very well.