I have a 12 year old son that will be a new shooter and I want to share an 870 Express combo shotgun with him for deer and for turkey. Should I go ahead and get the 12 guage because he should grow in to it soon or just get the 20 guage? What is the difference between the two in terms of maximum yardage and knock down power?

I was also thinking of getting a 597 22 LR for him to get started practicing with.

Any suggestions?

Thanks!