Stan,
I have documented the cause of wounds in over a thousand identified Confederates who were at Gettysburg, and all but a handful of these were from other than gunshot or artillery rounds. Two cases of gunshot richochet both involved large rocks which served to deflect incoming rounds and these occurred near Devil's Den and Little Round Top where granite boulders were plentiful. H. C. Coffman of the 3rd Arkansas was wounded by a ricocheting bullet that blinded him in both eyes, and John Malachi Bowden of Co. B, 2nd Georgia was struck in the thigh by a fragment of a bullet that glanced off a rock - Bowden attributed it to "friendly" fire. Among the handful of rare and/or unusual injuries were two cases of bayonet wounds, a mounted officer who was toppled from his horse by a minie ball and impaled himself on his own sword, a soldier wounded by a clubbed musket, a soldier injured by a falling tree limb no doubt broken off by an artillery round, a soldier who received splinters from his musket stock, and another soldier wounded in the ear by a gun barrel that flew from the hands of a comrade. Among the artillerymen, one was injured by a capsized cannon, and another was wounded by a flying piece of wood from a wheel. I have not completed a similar study of Union forces at Gettysburg, but I do show a case of a soldier injured in town by falling bricks knocked off by an artillery round, and another soldier wounded in the testes (ouch!) by a rail on which he was sitting, which had been struck by a solid shot from a cannon. By the way - Go Navy!