I wonder how a 270 WSM would fit a 12 year old kid as a first rifle. The WSMs don't really weigh much less than a standard magnum due to the need for the 24" barrel. I would buy the youngster a compact 7mm08 like a model 7 or Browning Micro. When he gets physically bigger then get him a standard size magnum for elk but my guess is he will never part with the 7mm08 as a deer rifle and it would serve as backup for elk.