I think a gas operated 20 ga would be a better way to go.
My boy is tiny and has been shooting a weatherby SA-08 youth since he was 8 and weighed less that 50 lb. We started with low recoil 20 ga and loaded one at a time (obviously) but it really didn't take long for him to get used to it. First couple of times he only shot 10 or so but he was 8.
He is 10 now and only about 65 lb and can shoot 100 trap with no issues.
One in the buy and sell right now. It's been a good gun for us. 5 or 600 rounds maybe. Only cleaned it once when it was new and it is running fine.
http://www.outdoorsmenforum.ca/showt...ighlight=youth
