It only took one grenade to destroy the combination lock and top section of this gate. I do not know the history of the gate but it had no visual damage.
In the video it looks like I might have placed the grenade through the wall and it dealt damage to the inside section. I'm not sure how this mechanic works though.
If this is reproducable it will negate the new tougher base raiding system.
Video: https://youtu.be/Of8r_pz9Aec