Not an RPK barrel, a heavy barrel like a PolyTech and in a reinforced recvr for grenade launching.
Yugos have a history of being ready to support grenade launching in their modern rifles.
Versions of their SKS have grenade-launching support built-in, as do the M70AB series with the launch sights/gas valve; just add the launcher flashhider off of a Yugo SKS.
Pre - or post-breakup, the Yugoslavs have a rich history in small arms and marksmanship.
The NEW Zastava PAPs are arsenal-made AKM-derivatives from what is now Serbia, and are built using factory barrels, reinforced rcvrs, but with narrow trunnions, single-stack bolts, and are not cut-out for double-wide mags.
They're imported, 922'd, and hi-capped in-country.
MANY have had no probs with single-wide bolts and double-wide mags. They are outstanding guns. If you missed the boat on the Century M70AB1 parts-kit-guns - here is your (possibly last) chance to own a "Yugo".