It says they have 4,600 HP, but when I shoot them seven times with GRL, which would do 5,040 damage, they don't die. GRL doesn't take damage bonuses, so the damage per shot should always be 720. 5,040>4,600 so the health might be wrong.
Here's a gif of me shooting it seven times and it doesn't die. https://gyazo.com/613e2a1c3dfdf01dbc639688689f8690