With my kids the thing i saw early was flinching. SoI started training them with a Suppressed 22lr. It has made a world of difference.
Shot placement is everything! I would rather take a round of 50BMG to the foot than a 22short to the base of the skull.
all 21 of my guns are 45/70 govt 357 mag, 22 or 12 ga... I believe in keeping it simple