The AMR-B05 Alien Assault Rifle is a very powerful gun used by Prawns. The first gun presented to Wikus van der Merwe (by the MNU scientists) at the underground shooting range at MNU headquarters, the Assault rifle makes short work of the porcine kadaver strung up for target practice. In District 9, the Prawn assault rifle was used by Christopher Johnson in the attack on MNU headquarters.
This is known about the science behind the Assault Rifle, according to Designer Greg Broadmore:
"The tubes down the side each discharge an explosive burst of gas one after the other down the length of the barrel behind the projectile - a linear accelerator gun, like a rail gun but without the magnets. Of course it would fire these all rapidly to get a high rate of fire."
The csgo skin series "Asiimov", is based off of this weapon.