Pressure testing of equal weight payloads (ball or shot) has shown that pressures are higher with shot loads. It is believed to be due to the shot charge "squatting" under acceleration and trying to expand radially. The round ball can not do this, as it is a single mass of lead. I've found that a 12 ga. ball at 1200 fps is more than enough to kill a deer, the ball punches a large hole straight through. Recoil is no worse than a trap load, an ounce of lead is an ounce of lead. Modern day deer slugs are loaded to 15-1600 fps, quite lethal but brutal to the shoulder. You don't need all that speed!