If I'm wrong, please correct me guys. I would load a 50 and a 30 777. and a medium weight bullet or sabot. The size and weight of the Lead is what is going to kick. My wife killed a doe at 56 paces from the bottom of her tree stand with a caplock .50 pistol and 65 gr. FFFg and a patched round ball. She broke both shoulders. Saw and heard her shoot from my tree stand, rushed over. The deer was dead where it had stood. I guess the best thing is to work up a light but lethal load the child is comfortable with. The main thing, is comfortable. We don't want a kid starting out flinching.