Still had my old JC Higgins Model 41 as a possible donor by shortening the stock. Instead started my son with a RSI Anschutz WoodChucker (exhibition wood.. yeah I know, proud papa went overboard). Beautiful little rifle, exceptionally accurate, 5-shot bolter, perfect except he outgrew it all too soon.
The TC Hot Shot is a very safe starter carbine in 22LR, they offer stock extensions as they grow, and for a pretty low price new.
Better on this platform, an old TC Contender or G2 Contender Youth Model carbine that will last them for the rest of their life with adult stock added, barrels chambered for up to 250 plus different cartridges for any kind of shooting/hunting (and do double duty as a specialty handgun).