Remington Model 788??

With the small bolt face, you're pretty well limited to a cartridge of similar size - .222 Magnum, .223 Remington and such for standard chamberings. You can have it rebarreled and chambered in various wildcat cartridges (any of the TCU's as an example). Take it to a gunsmith and see what he would recommend.

The 788 is an awesome and underrated action. A friend of mine rebarrels every one he gets his hands on to .223 Ackley Improved.

I love mine in 223. One other thing you have working against you in the 222 action is that I don't think the ejection port is big enough to use other cartridges in. All that being said, my grandfather killed a pile of deer using his 222. He'd shoot em in the neck and they'd drop like a sack of potatoes. Ya gotta be picky on your shots and know your limits if your going to do that, it works, but it isn't easy.

If your dad's .222 is a shooter I'd consider leaving it alone. One of the most accurate factory rifles I've owned was a 788 in .222. 30 years later still kicking myself for trading it. Just for what it's worth, there may came a time you'd want a varmint or prediator rifle and it could fill that need nicely.

The last several years 788's are showing up at local gun shows with price tags in the $400 range. Not bad for a rifle that sold new for around a hundred dollars.