Just in case some of you AR47 guys might be interested, the newest version of the MGI Quick-Change-Barrel upper receiver system has the internal relief-cuts for accepting AK mags, just like is needed for the AR47 lower.
We haven't specifically tried it on an AR47 lower, but it works fine on our new MGI Modular Lower Receiver with the AK magwell installed.
If anyone wants to give it a try, we offer a money back guarantee if it doesn't work out in the application. I think it should probably do the trick, and you could use AK47 mags or AK74 mags, and switch out barrels to suit your needs in the QCB.
And, if you have the MGI modular lower receiver, you can quick-change the magwell to the AR15 magwell, and quick change the barrel back to a 5.56 barrel, and swap the bolt back to a 5.56 bolt, and have both calibers on the same gun, using the correct mags for each caliber. Sort of like "have your cake, and eat it too".
Here's a pic of the MGI Modular system with the quick-change barrel upper and the modular lower receiver with the AK magwell installed.