I got my son a .243 for his 12th Birthday. It's a Remington Model 7 Youth that came with a 3-9 scope for a little under $500. You can find youth packages that are a little less pricey if you look. Remington sells a Model 700 Youth for less than the 7, and there are nice youth packages sold by Howa and Savage as well. I'm not sure how big the deer are in Kansas. The .243 is plenty for our Texas Hill Country deer,but, the deer might get a bit fatter on all the corn and soybeans you guys grow up there.