I dont know anything about civil war howitzers though I do have an observation and a question. I noticed that the picture of the artillery shell at the bottom has a fuze cavity, whereas the other metal ball does not. I would guess that, even as early as the civil war, most artillery shells would have been designed to explode and spread shrapnel. I dont think that a solid shot would be very effective against a mass of men (except for the one, two, or three unlucky guys that got hit by the thing). I would guess that most of the smaller "field" or portable artillery would fire such projectiles. I guess there could also be solid shot for attacking fortifications. I'm sure that there is some experts out there that know.