When you fire a shot, a "cone" flares from the muzzle. This is a very quick short-range weapon, and is almost like a targeted SW: It fires only in front of you for about the space of 1/2 to 1-1/2 tank lengths, and you must be aiming toward your target else you'll miss. It will not hit anything behind you, nor will it hit someone directly to your side or above (or below) you. However, it will hit someone who is both immediately in front of you (within range of the cone flare) as well as to one of your immediate sides (top, bottom, left, or right).
It would make sense that this weapon does NOT ricochet off of walls (including ceilings or floors) else you'll be hitting yourself frequently. The flare burst is very quick, so being hit by this will account for a single "shot": you will lose your Shield flag but not be killed (as you can be by a SW or laser).