When my son decided that he wanted to start deer hunting, I wanted to get him a rifle that he could grow with. I got a Model 700 in .270 and installed a 'youth stock' on it. Let him practice with the managed recoil rounds to avoid the dreaded flinch. Hedid fine with it and when we actually got on the stand, I snuck the full loads in. When he shot his first deer, he never felt the recoil LOL. I have never shot an animal with the MR cartridges but to me, they are ideal for the range. Anything to help kids get into the shooting sports has to be a positive.
By the way, I'm putting the full-size stock back on soon but I will continue to let him use the MRs until he gets a little bigger. Man they grow up quick!