Fact: Today I used heatsink for the first time since the flame nerf. In other words, I used it for the first time IN THREE MONTHS. That ammo type really needs more of a purpose outside of lumber/flak arming time help.
Fact #2: I didn't even use it for its intended purpose. I wanted to get an extra shot for the flare gun.
Fact #3: Heatsink is the best ammo type for close-range offensive flare. You can lay down 20 stacks on their balloon, and then hit their hull too.