Depends on the rocks. Some areas have stone that fractures with sharp edges, other rock is softer, and the edges are not as sharp.

Last winter we were in a "sharp rock area" (The American Girl Mine in So.Cal. We are now in a softer rock area (Eastern Rim of Arizona). I still find cuts in my tires, but they are not the razor clean cuts we experienced near the American Girl Mine.

The general feeling of the forest service folks I have talked to on the "East rim" here in AZ is that there are a lot of slow leaks in their tires, but seldom a large failure.

No matter how you cut it (<<pun), tires take a beating on gravel roads.