The Pistol Club I attend has an incredible program for youths...a former Olympic pistol coach coaches the youth for free. One of the points he stresses is curing flinches (or preferably, not allowing one to form). They use a recoil-less airguns, and Mr. Wang said the kids will still flinch at the sound of the airgun pop. He stresses the use of very good hearing protection, even with an air gun. My recommendation is 1) he use the airgun with hearing protection. Do NOT let him sight the gun, but let him pull the trigger with a pellet in it. This way he will be focusing on trigger pull exclusively. (obviously the gun will have to be pointed in a safe direction). 2) When he is squeezing the trigger without a flinch, graduate to a .22 and do the same thing. Then go on to the .243 or .30/30. Either is a good choice for deer or antelope, but I would choose the .243 because you can multi-task with it for varmint shooting or fall turkey hunting.