Oh, and take the loudener (flash suppressor) off of it or put a linear flash suppressor on it. That will make it more pleasant for the little guy to shoot. He won’t need hearing protection in the woods either
First off, good luck taking a 6 year old. Been there done that. That being said, make sure the gun fits him. Pull out one of the ARs with a collapsible stock. Easily adjustable to small shooters. Preferably with a scope. 5.56 is not great for deer but with a confident shooter and a soft point...