If I were designing a “starter rifle” for a youngster - although 12 is pretty capable - I would look for an 18-20” sporter barrel bolt gun in a Remington 700/Howa 1500 (or mini) weight action, adjustable stock (up and out), in something middle of the road like 6.5 Grendel to 243win, threaded muzzle for either a brake or a linear compensator.

I go back and forth on what I think should be done for legacy and heirloom planning. In general, a kid will want something new eventually, so sometimes it doesn’t make sense to spend too much on the first rifle. Alternatively, some models could be restocked or adjusted to fit a kid as they grow, and handing a rifle down from one generation to the next is a grand tradition. One easy mistake is to put too much rifle on them, either in weight, size, or recoil, such they don’t really enjoy the rifle and either don’t enjoy shooting at all, or can’t wait to get something else.

In general, I wouldn’t recommend a .30-30 for a first rifle, but I can absolutely appreciate the interest in handing down a legacy. If the kid likes the rifle, then maybe father and son (and grandpa?) could plan a hog hunting trip to put the rifle to good use, instilling a sense of legacy in the rifle and making memories together at the same time. I handed down my grandpa’s/dad’s single shot .410 to my son. It had 3 generations of use and abuse all over it - extreme neglect before I got ahold of it - so I refinished it, replaced broken parts, bought a new barrel to cut down for youth use, and two new stock sets; one to fit my son now, one for when he grows into a full LOP. I also spent money to rebarrel and rescope my first deer rifle to make it more useful for my son when he gets big enough to manage a Ruger weight rifle with the recoil of a .30-06.

For my son, I have a 5.56 SBR build planned, plus a Remington 700 short action. He’ll get the PT&G 700 first, running a single shot insert and a short stock, with a 16” barrel in 6 Dasher, and a low magnification red dot on top. As he grows, it’ll get a new barrel in whatever cartridge he prefers, a new stock, and a new scope. It’ll be expensive, but it’ll grow with him.