ryban, looks like you got your answer. The .260 or 7mm-08 would be my choice. Check out the Remington model 7 youth. It has smaller stock dimensions to fit smaller shooters. Not sure if Ruger or Browning make a youth model. You could always search the net and find out. Good luck and practice with your new rifle when you get it. Not only on the bench, but sitting down on the ground too and prone, and even off hand.