WELLFLEET — A military projectile possibly dating to the World War II era has been destroyed after it was found on a Wellfleet beach.A fisherman found the device in the sand at Marconi Beach at about 3 p.m. Wednesday and alerted authorities.The state police bomb squad responded and the device was blown up on the beach at about 7 p.m.Officials kept curious spectators about 1,000 feet away from the explosion to protect them from shrapnel.