Hello!
This is just a simple build I put together for the new Tetra, where the main focus is around the semi-fire mode(or as I like to call it the 40mm Grenade Launcher), which has the added effect of going through walls.
You can switch out any of the elemental mods for whatever fits your purpose but this is what I usually run around with.
The main problem's I've run into with this build is the slow rate of fire or the fact you run out of ammo fast, because you're launching the entire magazine, to counteract this I just go for the mutation mod to help out with the ammo issues and go for [Primed Fast Hands] to increase the "fire rate".
You can also pop in the new Primary Arcane (PRIMARY MERCILESS) onto this puppy for the extra reload speed which will help out a lot.
I'd say it's pretty effective with most types of enemies, but you may run into problems with the special/heavy units from the grineer/corpus (especially with the nullifiers/anything that has a lot of armor).
Overall this weapon feels super nice to run around and clear mobs with, but from what I could tell it doesn't scale that well.
Here's my personal score for this weapon:
Effectiveness: 8.5/10 (Does it's job well, can kill enemies through walls and has a really good explosion range)
Scaling: 6-8/10 (Wouldnt take this along for long - very long missions)
Fun factor: 9.5/10 (Feels good shooting the damn thing.)