I've got a Fireball built on a Stevens 200. It's pretty much a single shot, which doesn't bother me. Shoots great, more killing.
If I did this again, I'd look for a claw-extractor, Mauser style ejector setup because the cases are so short. I reduced the tension on the ejector spring and cases eject properly about HALF the time. Stock spring, they just went cattywampus and died inside the receiver ring.
As for magazine feeding, somewhere along the line I'm going to hunt down some cheap pistol magazines or even 30 Carbine hardware and start chopping and hacking and zapping tin. If you can get a Carbine follower and spring to fit in the FRONT of the mag box with a good spacer, that should work. ANOTHER thing to try is an ejector in the rear space, make a slot in the lower left quadrant of a "experimental" bolt head.
Hmmm. Maybe this winter. And if it works, I'll be RICH.