I THINK THE EJECTOR IS THE SAME ON MANY OF THE SMALL RINGS BUT I KNOW VERY LITTLE ABOUT WHAT WILL AN WONT FIT.
The ejector shoud be easy to find. I wonder if they're specific to the model year or if they're all interchangeable? Since you're not pressed for time you can do some trolling on ebay to find the trigger and a stock. The savage type locknut is a good idea. There was an article on doing that in SGN a year or so ago. I've done it with a ar15 barrel and found it was a little more forgiving than standard chambering.