.22LR Conversion kits

Does anyone have experience with these? I want to build another rifle, and the only way I can justify it is if I'm building it for my son (he's . So, I'm considering a .223 Wylde build, and just keep the BCG in storage until he's old enough to graduate to a larger caliber.

So, I've been looking at these conversion kits. Bolt and magazines are included - but I wonder about the reliability and if .22lr will fire in a .223 Wylde chamber.

This item is new, $265


Used Colt model, single 10 round magazine $200


These are used, and auctions - so I don't know how high they'll go