your youngster is 10 and you mentioned (I assume) he' s not tall.

By this I' m assuming you are willing to cut off a stock to fit him.

The ideal gun is a Rem 7 rebarreled to .257 Rob. or .250 Savage.....spendy

You really should reconsider the .25 caliber requirement. The .243 is a fully adequate rifle for deer. It' s not at all a handicapp!!