my son ( now 11 ) started ( age 6 ) with a bolt action 795, with a clip ( yea screw you I say clip ) of 7 rounds, started with no glass, then glass to finally learn how to adjust the glass, the best training tool, now he shoots his .243 with no issues ( still a bolt action ).
But I have to admit, he plays with an M&P 15-22 well dressed, that is what he asked for when he brought all A 2 yrs in a row ( and on that path for year 3 ) , so, not a bad incentive in my eyes.
Now my opinion, the Umarex ( Colt M4.22 ) sucks, the GSG and Sig hard to glass up if you want co witnessing with BUIS, the Ruger 522 is ugly, and if you want inexpensive tacticool the new Mossberg at 219.00 is the winner.