The Auger WS shares many traits with the regular Auger, including the same ammunition. It is more or less the same rifle with just a few modifications, like making it lighter for humans to handle. It can also be fired underwater due to it's rounds being energy projectiles. This special type Auger found only in Resistance Retribution also deploys a better shield surrounding the whole front of the player with a energy shield instead of just a simple barrier in front of the player.
The Auger WS is likely to be a modification of the Mk. I Auger rifle found in Resistance: Fall of Man, as both rifles generate shields that don't allow rounds other than Auger rounds to pass out of it.