The Blackstorm Gravitational Singularity Projector is the brainchild of weapon designer Eli Wegner, one of the few humans who earned the privilege of serving with asari commando units. Overawed with how the asari could create biotic singularities to pull opponents out from behind cover, he was determined to duplicate the feat technologically.
Wegner's team created a weapon that could elevate target particles of matter to near-infinite mass, creating a gravitational singularity and drawing nearby objects inward for a short time. The rapidly-increasing gravity rips the target apart as it pulls the enemy closer to the singularity's center. When the mass effect field destabilizes and suddenly returns to normal mass, the result is explosive, and inflicts additional trauma on the enemy.
The weapon almost didn't happen. Early designs were dangerously unstable: the science for creating a hyper-dense mass effect field was well established, but projecting it at an adjustable range proved elusive. It was only after six years of development that the weapon finally qualified for Systems Alliance AIHW (Advanced Individual Heavy Weapon) trials. By that time, the singularity projector was rugged, reliable, and easy to use and repair. It immediately went to field tests in a small-scale desert war on Earth where the weapon terrified opponents who had never seen its effects before. The swirling sand and dust sucking soldiers into its center served as the centerpiece of many propaganda videos. In the resulting media coverage, the Wegner Arms M-490 GSP became known by its simpler nickname, the "black hole gun." His dream finally a reality, Wegner personally altered its name to the more marketable "Blackstorm."