The possibility of rechambering is probably the one shining point of the cartridge. Blackout is what happens when one realizes how underwhelming the whole idea is, when multiple yawns compress , like hitting the sound barrier, and a sudden nap ensues. I know that many enamored of "black rifles" and the AR "platform" would be all excited about this, and so they should, but the Handi "platform" is not about how many rounds you can put downrange. It is not about picatinny (sp?) rails and how many accessories you can hang on it. It is not about increasing the "tactical value " of the weapon. Somewhere there are probably individuals that envision a handi with a collapseable stock, a rail with a scope, rangefinder, bayonet, tactical light, bipod, temperature, humidity and wind gauge, GPS, silencer, and microwave. I cannot think of anything further from my outlook.
I see a handi as the simple embodiment of individualism. A single shot, delivered from a minimailist package, where the outcome it the result of the effort and talent of the user, not how much trick technology one can afford. I think that the highest example of that are the Maxi's out there. A hand reamed barrel for a chambering that is no longer commercially produced, hand loaded with a cast bullet poured from scrap metal that is a work of art, formed in a garage somewhere. Loaded to specifications of the shooter alone, for the single gun it will be fired from. The only thing better might be a Herrett, as you would also form the brass yourself.
I guess we could push for a 45/90 single shot on an AR platform, no magazine, and set up to use black powder.
Other than the availability of possible brass, what could be the advantage ? It would not lend itself to cast loading well. Subsonic loads? Go heavy cast from a 357, not 220 gr jacketed, and why?, we cant use silencers to hunt with, and the license and paperwork are a nightmare. A 327 would at least have 4 different brass one could use, and be a good small game cartridge with wide power and cost range. Even a 6mm TCU would have been somewhat more practical, you would not lose so much brass and have to anneal shoulders and necks. Just my 2 cents , well, maybe 25 cents worth.