Some day.
However, I wouldn't put all my eggs in the 5.45x39 basket.
You're solely dependent on former Warsaw Pact manufacturers, of dubious quality, and ALL of that ammo is imported through U.S. Customs.
There are neither domestic manufacturers, nor handloading components for that chambering.
I actually looked at forming brass from something else, and swaging 5.56mm bullets when I was getting excited over the East German 5.45x39 bolt sniper guns that were coming in back in the day.
IIRC, it was either an Executive Order or BATF edict that killed steel-core 7.62x39 after Thomas Spithaler's OA-93 AR pistol fiasco.
That's a mighty thin logistics tail, easily severed. If you've already got a stash, or can lay in a decent stash, I'd say you might have some fun for at least a while.
Just keep your .223 upper handy.