Hi, x!

The hardness of the steel can vary throughout the blade and from blade to blade. Steel is a mixture of metallic crystals and S7 likes to form both martensite and bainite crystals when the steel is hardened. The martensite is hard and quite tough, but the bainite is slightly softer (yet much tougher and more flexible). Patti or Dan mentioned a heat-treatment process they use called martempering. Martempering relieves the internal stress of martensite crystals in a way that's less stressful on steel than traditional quenching followed by tempering. It also increases the chances of bainite forming in the steel (if you want to get more technical, the bainite in S7 is usually lower bainite and the martensite is usually lath martensite - both of those are insanely tough). What the extra bainite does is cause variances in the steel's hardness. Even the martensite will have various levels of hardness.

The RC scale is neat, but only provides a sole point of reference. That point of reference is the depth of a dimple a diamond point makes in the steel with a set amount of weight (the smaller the dimple, the harder the steel). While harder is better than softer to a point, it doesn't tell the entire story. There are some very hard steels which will stay sharp forever so long as they only cut food on a wooden or plastic board (what's called "Japanese" cooking knives comes to mind), but can easily be ruined when used outdoors. There are other very hard steels which need an edge thicker than a cold chisel or else they'll rapidly dull, and heaven help anyone who cuts metal with them and doesn't expect to do a lot of sharpening. And then there are steels used in the same range of hardness as ScrapYard's SR77. Most lack the impact toughness and several lack the ability to take a fine edge. Those steels have their advantages, too, but not as survival knives, hard use tools, or harder use entertainment.

Hope that helps.