I've purchased two youth rimfire guns.
First one was a Henry Mini-Bolt. Gun is a single shot bolt action with open sights that is well proportioned for a 7 year old. It's light weight, easy to load, action opens/closes easily. Striker must be manually cocked after the action is closed for gun to fire. Extraction and ejection was 90%. Trigger was, being charitable, fair. Gun was reasonably accurate, although the sights were a limiting factor once the shooter gets the basics and wants to start mastering marksmanship. Gun has no means to upgrade sighting or add a scope without major (expensive) surgery). I recommend this gun if you want to train a child in basic gun handling and safety, but I think it will be easily outgrown if the child becomes a serious shooter. My son liked the Henry, but the sights and accuracy were frustrating him and his progress as a marksman. I paid $160 for this gun new.
http://www.henryrepeating.com/minibolt.cfm
Next we bought a CZ Scout Youth trainer. Gun is based on the adult's 452 action with a shortened stock and barrel, and is well proportioned for a child, slightly larger and heavier than the Henry. Trigger is adjustable and very nice. Gun comes with a single shot follower and magazines (5 and 10 shot) are available for about $25 (!!); 5 shot sits almost flush with bottom of stock, 10 sticks out and can interfere with hand placement on fore end. Action on the CZ is tighter, especially when new, but does smooth up after a couple hundred uses (I put JB Bore Paste on the ramp and worked it for about 10 minutes, now its super smooth and easy to operate). Gun will fire when action is closed (no manual cocking of striker). Safety is tight, my son has a hard time operating it (he's real good keeping his finger off the trigger
), but should smooth up with use. Sights are pretty good. I put a Simmons 4X Mini-Mag scope on this gun ($29, incl. rings) and am able to consistently shoot sub 1/2" 5-shot 50 yard groups with PowerPoints and Thunderbolts. Yesterday my son hit straight strings of 11, 9 and 7 Chicken silhouettes from 50 yards. He (7) loves this gun and said he does not want to shoot the Henry any more, giving me permission to sell it (got $140). If I were to do it again and did my homework properly, I would have bought the CZ first. $170
http://www.cz-usa.com/_p/pdt.php?id=45
http://www.marlinfirearms.com/firearms/boltAction22/15YS.htm and
http://www.roguerifle.com/ are two other options, but I have no experience with them outside watching a boy shoot a Chipmunk once. He was a big kid and was unable to cock the manual striker (like Henry) without really fighting with it, which created muzzle control safety problems on the range.