On an occasion where Duncan is shot, no blood splatter or wound is visible at any point, however, when he is seen later, blood is visible on both his upper back and upper sternum, implying a through and through shot.
On multiple occasions implying gun shots were fired, no muzzle flash was visible nor were there any other apparent signs a weapon had been fired (i.e. smoke, shell casing, bullet wound, etc.)
During the initial court house breakout scene by gang members disguised as painters, the sound of gunshots can be heard quite audibly, though the pistols being used are visibly equipped with sound suppressors.