The Zone of Alienation mod is an adaptation of the renowned AMK mod. It is built on top of a specialized variant of AMK that uses a magazine system. From this premise, it has expanded to aim to include the following:
I've made some changes to Strelok's AK, it is no longer rapid, but instead it is now a heavily-modified AK-74 that is chambered in 9x39 and uses internal components that were scavenged from an OTs-14 Groza.
I based its design off of a similarly modified rifle:
Absolutely great idea.
I thought very hard about whether or not it would be balanced to include this sort of weapon at the stage of the game where you find it.
The fact of the matter is that yes, you do find this weapon in the Agroprom underground, but there is one catch here. It's most likely the only 9x39 weapon you will find early on in the game. However, it only comes with one filled magazine, and generally speaking, you don't find any 9x39 anywhere in ZoA until immediately after X-18, or in a few stashes in Agroprom, Garbage, and the Dark Valley.
Thus this rifle presents a dilemma. The player can either take it, and make use of it's meager 20round magazine to completely roll the opposition in the underground while conserving ammo, only to carry it as dead weight to the Bar, or they could make the other decision of leaving it behind and coming back later when they find ammunition for it.