I've never been a good economist, so ya probably need to take this with a grain of salt. I'm also a hoarder and a scrounger. I keep a lot of stuff I don't see a near future use for. That being said, I'd shop the internet and buy a complete rifle, pick up an adult stock here in the classifieds, and keep the youth stock for a kid down the road. If you buy a non-factory fit barrel, you may have to modify the frame. If you do, the original barrels won't fit properly. A new rifle isn't too much more than factory barrel, and you have more bang for your buck. All the above is how I get in trouble with my wife from time to time.
Pete