So I've been playing around with some of the weapon augment mods, and a few of them are really good. My favorite so far is this one, mostly because it's for the Burston Prime, a gun I already like:
It basically replaces a Shred mod (30% fire rate and punch through) in my normal Burston Prime build, so I'm getting an additional 50% fire rate plus it now procs like a syndicate gun...in this case "Truth", which recharges your health and procs gas damage. I think as a practical matter, I'm finding the health recharge more useful than energy, since my frame builds all start with efficiency. Available from Arbiters of Hexis.
And when the Gammacor gets nerfed, this is your replacement right here:
The Vaykor Marelok hits like a truck (about 8500 combined damage), is accurate at range, has a clip size of 10, and procs "Justice" (Health plus Blast). In normal use, it feels a lot like the Brakk but with more range and a larger clip. Available from Steel Meridian.