If all it took was a phone call and some cash to get things like the RPK74 drum mags, 60rd quad stack 74 mags, and Bizon drums then someone surely would have done so by now.
In theory, all you have to do is find someone with the mags to sell them to you, then get an approved Form 6 (import license) for them. In reality, there is a 1996 trade agreement with Russia in effect which prohibits the import of most milsurp arms items like parts kits and such. They specifically exempted the Saigas and a few other "commercial arms" which is why we can still get those, as well as ammo. IIRC, you have to provide proof any controlled Russian origin item has been out of that country several years before they can even be imported from a different country. Ask 4thIDVet about that, he tried getting some russian origin imports in from SE Asia a while back.....
In addition, Russia pissed off the US state department a while back by selling naughty toys to countries we don't play nice with, so they cut off the legal imports too. One of the reasons Saigas, Wolf, and other Russkie ammo disappeared for a while. Either those sanctions have been lifted or they found a workaround since the stuff is flowing again.