So, we have Hammertime and the IRAC already, but...
Alt. B:
I got lit up by one of these on Mirage a couple of days ago. He was chain-firing off of what felt like two triggers, since I got hit by two staggered pairs of shots (serves me right for planting my backside on top of that hill and spending too much time birdwatching aero hunting instead of paying attention to the ground like I shoulda been). Sounded like I was on the inside of a gong... *BONG BONG... BONG BONG*. It certainly woke me up.
So, what's designed to get someone's attention and rings in pairs?
I vote we call it the "Doorbell".
Also, Alt. E:
As I was writing this and referencing the wiki, the description of the Alt. E reminded me of a weapon from another game. Anyone else here played Bulletstorm?
I vote we call this thing the "Boneduster". Based on my single (very brief! ...ow.) encounter with one so far, it seems to live up to the name.