Afterburner is a custom Elemental weapon and the custom version of Flamethrower.
An upgraded version of the Flamethrower, the Afterburner has low damage, but a very high RoF and good accuracy. However, like all elementals, it is plagued by short range and the risk of suicide. Being a custom weapon, its special is Reduced Ammo Consumption.
It is the worst elemental weapon, after Flamethrower, which is the worst. Don't even think of building this blueprint in the first place. If you did, consider yourself the biggest idiot on the planet.