Hard material can be displaced by firing a frangible projectile from a firing device. The projectile has a rear portion that engages the bore of the barrel of the firing device and a front portion that is rotatably journaled to the rear portion. The front portion can be frangible to allow maximum displacement of the hard material. Specifically, the front portion has a core and a plurality of fins extending from the core. At impact, as the fins penetrate the target, the fins separate from the core and spread radially outwardly from the core.