I agree with Sheridan - a semi auto has less kick/recoil felt than a pump gun and thus one could use a bigger gauge shotgun.

Many single shots have a high recoil. To reduce that recoil in any gun used - use a lighter load. A good load would be a simple low brass trap load in 7.5 or 8 shot. (Note: on all other game except turkey where legal- #4 - 2 3/4 Turkey loads will work here)

One does not need Magnum shells to harvest game. Just teach the youngster to make good shots at a much closer range. A 20 gauge 2 3/4 #4 shot round will kill a Tom turkey at 20 yards easy if the shot is well placed to the head. Trick is to take the shot at less than 20 yds.
JW

JW