HK 47 is iconic, he better be ******.
That said, I remember him sniping non-stop in Beta too, but he only gets 2-3 snipes per phase, no? Giving you time to heal up during the immobile phase
He was sniping upwards of 6 or 7 times in a row doing him today.
He would do part 1 normally, flamethrower > knockback > 3 snipes
Teleport, summon adds
Then 7-8 snipes in a row. In the few times we were lucky enough to survive it due to good RNG he would then teleport to the middle and activate the power core. As soon as we freed him he would begin nonstop sniping again. We made sure he was always tanked and always had someone in melee range so that wasn't the issue.
I remember him doing the 2-3 snipes in a row in beta but I don't remember them two shotting people. This was just chains of 3k hits over and over again, if it hit the same person two times in a row it was just game over. When the adds were out on top of the snipes the damage going out was nowhere near healable.