Large guns were usually placed before or at the start of a battle, and then would not be moved until it was over. These would be at the back of an army, on ground that gave best opportunity to fire at the enemy's positions.
These bigger guns tended not to be placed too far above the battlefield, since depressing the barrels caused problems. The ball could roll out, or when fired would not travel as far as expected.
Lighter pieces were positioned between regiments or brigades, and could be loaded with shrapnel.
Shrapnel could consist of all kinds of junk metal that could be gathered, and was effective against
enemy troops at close range.