The piece on the left is a shell fragment. The round brass piece is the center part of a fuse from a Schenkl Shell. Here's what it would have looked like in the shell.
The whitish lead piece is a finial from a percussion cap box - most likely Confederate. It was also likely carved by a soldier from a bullet. The dark part on the finial is actually some remaining leather from the cap box - still there after 150 years. I recovered all of these items recently on private property here in the Shenandoah Valley - with permission from the landowner, of course. Stonewall Jackson was on this field.