The RPK Light machine gun is one of the four LMGs and was added via with the second Gage Weapon Pack. Out of the five LMGs, it is the only one that doesn't have a reputation lock, meaning it is instantly available after the DLC has been bought.
Even when aimed in, the RPK (as with all LMGs) does not use sights, so a laser module is recommended for accurate aim (but see tips below).
Ammunition is fed from a detachable drum magazine, allowing tactical reloads. A tactical reload takes approximately 3.3 seconds, and an empty chamber reload takes approximately 4.3 seconds.
At first glance the RPK appears inferior to the Brenner 21; despite having the the same firing rate, it has a smaller magazine of 100 rounds, slightly lower accuracy, and less damage. However, it does make up with its higher stability and shorter reload time. While the Brenner 21 has a major problem with recoil on full auto, the RPK has much less and so is able to stay on target much more easily. This can be boosted even further with certain mods, making the weapon almost as stable as any assault rifle. This means that one can empty out the magazine and stay on target much more easily than either of the two other LMGs; however, the poor accuracy (relative to assault rifles) does mean a few of the shots will miss.
Properly modified, the RPK can maintain high accuracy, good stability, a modestly improved damage output, and versatility via a laser attachment for both snap- and precision-aiming. This makes the RPK capable of dishing out high damage accurately with careful aim, and the ability to unleash a powerful, wide-spread bullet storm at close range at a moment's notice.
Although the small magazine will require more reloads, the reload speed is much shorter than other LMGs (even when compared to the Brenner 21), at a speed equivalent to assault rifles, thus making tactical reloading much more viable than the two other machine guns. Indeed, properly specced, the RPK can serve as a heavy assault rifle with much greater ammunition reserves than normal, albeit with the 20% movement speed penalty while wielded.
Even when other light machine guns are unlocked, the RPK still remains a powerful tool of the trade due to its versatility. It is an incredible starting weapon that one can use on virtually any difficulty, and a weapon one might keep for quite a while as they go through heists.