Remember children's needs are different in as far as length of pull, and a lighter trigger.
Most children will need a length of pull that is around 11" so that they can see through the scope easily. Children's fingers are not as strong as an adult's, so replace and adjust triggers accordingly.
Range time to a child is as good as hunting with their dad.
A 22/250 loaded with 60g Nosler partitions is a dragon slayer, they may never want more. Then a 243 with 100g Hornady BTSP or Flat base, or a Nosler partition will take out large frame deer at 300 yards with ease.
There is a lot of difference between an 11 year old, 13 year old, and at 15.
A common brand of factory rifle, where you can get replacement stocks, cut them and fit to the youngster as they grow will keep them and you interested in shooting.
We used Thompson Center Contenders in 30/30 and 7/30 waters with some of the nephews, they are light, unreal accurate, and they are easily handled by a youngster due to length and weight.
We grew up poor, dad had a rule, no children shooting full size guns till we were 15, then many rifles and shotguns would fit the children(they could handle them).
Easy way to measure Length of Pull for a youngster is to get them to bend their trigger finger, then measure to the crease in their arm where it bends...get ready for a shock!
