From the rules.... Any design of pellet that is completely constructed of lead, zinc, or their alloys, may be used, in 0.177, 0.20 or 0.22 caliber. Must shoot under 20 ft/lbs of energy.
Good point, but considering the fact that "single finger guy on the springer" damn near cleared the course shooting a 46/48 with his springer, I'll let him worry about his technique