For all the achievements in Call of Duty: Black Ops 4 Zombies, besides the ones relating to the quests, you can use casual mode, but cannot
This one I heavily recommend playing on casual with 3 bots. I was able to unlock this at round 35. Casual makes it much easier, and the bots with take some zombies with them making you less swarmed. For the packed weapon I recommend the ICR, because it is right on the wall in your training area. Pack it once, then repack it 4 times to get the full benefit of Pack a Punch. You do not want Brain Rot as your AAT, this will make zombies kill each other, and it wont count!
I would heavily recommend these perks, in this order: Stronghold, Dying Wish, Electric Burst, and Stamin-up.
The general strategy is to train in the War Room, and get a pretty long train going. Once the area is clear of any dogs, find a Nova 6 Crawler, shoot him, then immediately run towards him to get gassed
. You will know if you are gassed, it will sound like a flash bang, and act like an old concussion grenade, making your movements extremely slow. Take aim and unload. Do this a couple times to get the 50 kills.
Right now it seems glitchy, not counting certain kills, or sometimes not exploding, but if you keep at it, you should get it.
Sorry, this Game Clip has been removed