Whispers at one time indicated Steyr might issue a Blackout barrel for an easy caliber change in the AUG. Haven't heard anything for a few months. Now I'm wondering if there is an aftermarket barrel available and who the supplier might be?

I'd be amazed if anyone makes any thing for an AUG considering the low demand.

If you look at how complicated that barrel is, machining wise, and the number you would sell (three), then no one is going to start making them.
True, the caliber change would be quick and easy...