So I just beat Mass Effect 2, and I was wondering WHY nobody has done this. The guns are pretty original, and would work well in Blockland. Here are two, so you can see the model styling.
M-8 Avenger Assault Rifle

Accuracy: Moderate
Recoil: Moderate
Fire Mode: Automatic
Fire Rate: 850 RPM
Reload Time: 1.5 s
The first Assault Rifle you get. It's pretty much standard issue.
M-6 Carnifex

Accuracy: Moderate
Recoil: High
Fire Mode: Semi-Automatic
Fire Rate: 145 RPM
Reload Time: 1.43 s