Lyod flipped the selector switch, and waited a split second for the "Iced" (Infantry Combat Sight Display) to switch from the precise cross hair of single shot, to the circle indicating beaten zone of automatic fire. He then braced the gun on the windowsill and waited for signs of his partner. It wasn't long.
James cam tearing around the corner at full speed and then some, rushing down the open boulevard. Loping behind him, a small horde of reanimates. The gunman aimed low, and squeezed the trigger, the whine of capacitors quickly overwhelmed by the snaps of metal darts breaking the sound barrier. Trying to hit heads at this distance, especially when they were moving was a waste, but once knocked down and crippled, he could take his time and finish them off with the gun in sniper mode.
About the same time the last reanimate hit the pavement, a red indicator lit up on the helmet mounted site indicating the magazine was down to ten percent - six rounds. Just as well, it was time to switch ammunition types anyway. Standard iron darts were cheap and easy to make, but they were too heavy, sharp, and strong - they went right through, no tumbling or deforming - fairly minor wounds if they didn't hit something important. Killing was best down with the steel core semi-jacketed ceramic types. Much lighter, a small concavity at the front, and a bit of frangibility of the middle - not quite like real lead bullets, but enough to make human rights advocates uneasy.
The helical magazine fit in a well in the upper part of the stock - the weapon was a bull-pup type, like most gauss rifles, since they needed all the barrel length they could get for the magnets. It came out with a soft click, while the double column straight magazine went in with a loud reassuring click. There was an actual tab on the side of the magazine specially there to make that sound, so everyone could hear and feel the locking. Although it held only half as many rounds, the alternate shape made it easy to tell ammo types apart, and was easier to load than the big ones under tension.
One click of the safety put the rifle back into semi-automatic mode, and a quick twist of a key-chain mounted tool engaged the unofficial overcharge setting. Bad for the battery, but the hunting rounds just didn't fly like the darts, and military sights didn't adapt to non-milspec ammunition - but this made a good approximation.
Still struggling to move forward, a few reanimates were a ways from where they fell. A pair even managed to stand up, but then dropped down for a final time as the man on the ground finished off the early risers with his pistol. James turned around and looked up to his partner, gave a thumbs up and grinned.
He was still smiling as the Gauss round went through his forehead and then into the pavement. He was still smiling as the body collapsed in strangely slow motion. The impact might have changed it, but lying face down, no one could tell.
"Nothing personal - just money", Lyod said to the empty room."Birmingham pay a lot better."