A method and apparatus for drilling and penetrating hard materials utilizes a high velocity gun system that fires multiple shots of a projectile and an energetic slurry at the surface of the material to be penetrated. The penetrating device includes one or more firing barrels that are loaded with a propellant, a projectile and an energetic (explosive) slurry, and are controlled to fire in a preselected firing sequence. The projectile enters the material to be penetrated generating a hole into which the energetic slurry is also fired. The energetic slurry detonates upon contact with the material causing an explosion that further fractures the material and which blows the material out of the hole. The process is repeated until a desired penetration depth is obtained.