I'm kinda bored, and just wanna cream over one of my most favorite guns in the game.
Many people say that the gun is mediocre or doesn't stand out but I say otherwise.
Also, opinion alert: you may agree or disagree... if you do, post em' in the comments!
GAME FOOTAGE BELOW ARE POTENTIAL BOSS SPOILERS
1. Recoil control
Probably the best recoil control among the 5.57mm guns in the game, and at least top 5 of the non-lasers. Offset by high starting deviation and somewhat low firerate, which can easily be fixed from a variety of attachments and upgrade ticks.
You'll be getting Headhunter levels of accuracy in no time.
2. High movement accuracy and not heavy
I find it odd that the gun has really high movement accuracy (like, T800 levels) and doesn't slow you down while equipping it. Because of this the RPK is also my most favorite SMG in the game hehey.
This makes the gun very safe to use as, combined with the Recoil Control, you can strike enemies easily without needing to stay still.
3. Low heat
Since the last patch, the RPK has received a -10% heat production, which doesn't sound much but:
If you have an Alpha RPK, you can magdump all 45 rounds without overheating.
4. +30% Scavenging
A seriously underrated stat, scavenging increases the amount of chests and shops in the game (which is why I often prefer it over luck) and also increases all drops, including upgrade kits, cursed shards, artifact shards, ammo packs, and health packs (not only powerups).
So in some way, it indirectly increases ammo gain, healing and damage output too, among other things.
Great if you have ULTRA, DIVINE, or some other low-gain guns.
5. Acid
The highest damage over time effect in Synthetik. With full auto, it's easy to fully stack enemies with acid dealing like 3k damage per second. A terrific alternative to AP rounds for those pesky high health/armor enemeies (turrets/bosses).
Some people complain about the RPK's low per-bullet damage, but I think this ammo type compensates for it pretty well.
6. Ballistic Soft
Being an LMG, it's a surprise that the gun uses standard ammo which I think is part of why it's great to use compared to other LMGs: shield is no biggie, penetration is okay and RG players can just go ham with Soft Point if they'd like.
TL;DR
It's a great gun to use in just about any scenario, regardless of what class you use, whether you're fighting goons, turrets or bosses, or what other weapons you have. The RPK really has no strong downsides, or at least, no downsides that isn't easily fixed with a few upgrades. It has many pros and nearly-negligible cons.
It looks decent. I agree that it probably carries the stink from earlier renditions over unfairly into this patch. But I want to check you and say that in righting a wrong don't go overboard. I watched your video a couple of times and it's doing alright but even with loads of headshots you're not dealing tons of damage. The acid bullets are very good, but they take a long time to kill smaller units and that exacerbates the problem that the gun doesn't have the highest burst damage from direct damage either. The 5.57 makes it so the bullets scale well, but don't come with unit piercing out of the box. I wouldn't be so quick to pigeon hole the gun based on it's caliber and magazine size. There is space between AR and LMG, current rendition would be knight's armament LMG which is a LMG but can fire 5.56 Nato or 7.62 Nato depending on application.