I saw that video a couple weeks ago. There's absolutely no pulsing in the fire rate, whatsoever. It has the RoF of a Doctrine/Arminius, but the impact (7) of the Hawksaw. The impact of a 100 RoF AR is 2. Doing the math that's a TTK of 3.5 faster than a Doctrine. It's also worth noting that the Hawksaw's stability can reach 100 with the right perks. I studied the film closely to verify the weapon I just saw annihilate the other players was a Hawksaw, and it was. Not only did I visually verify in-game, but the person recording the game went inside the player's inventory and verified it was a hawksaw. I have zero idea how it was pulled off.