When the chips are down, operators want the deck stacked completely in their favor. This means as much cover as possible between them and an adversary’s fire, and as little as possible in the other direction. That’s because military and LE professionals are painfully aware of the laws of physics. Projectiles will continue until they either hit something soft, or they are pulled to earth by gravity. Since adversary skill, not just physics, ultimately determines projectile accuracy, tactical capability—a good sense of defilade—helps operators overcome their adversary’s skill. Advantages in addition to defilade are good if you can get them.
So, the cardinal rule for anyone in a fire fight is to fire at exposed targets and avoid exposure. In many cases, however, especially spontaneous attacks, the act of firing back can require considerable risk by forcing troops or officers to stand open against incoming rounds. Since weapons today generate curtains of precise fire, this risk is dire indeed.
In these situations, probably every solider or police officer would give just about anything for a weapon that defies physics and shoots around corners. The idea isn’t new. In fact, inventors have experimented with curved gun barrels—usually to their regret— since the invention of gun powder.