In contrast with the L30 Gatling laser, this model is not only fully automatic and with a much larger ammo capacity, requiring a back-mounted battery pack, but was also mass produced for military use. While they entered service shortly before the war, they quickly became an important part of the arsenal, both of pre-War and post-War factions.
The Gatling laser is the most advanced weapon type for the Big Gunsskill. It is similar to the minigun, however, the Gatling laser is actually not a Gatling weapon, as the barrels do not rotate when it fires - instead, the barrels fire in a rotating order. However, although the animation for this firing makes it appear very random and haphazard, the barrels do not have to 'wind-up' making the Gatling laser much easier and quicker to use than the minigun.
At long range it is actually an incredibly accurate weapon, but performs poorly in V.A.T.S. One can easily take out any threat at a safe distance with a Gatling laser, however.
At point blank range, it actually aims a bit lower than the crosshair. This is easily observable when trying to shoot a corpse's head off while standing on top of it.
Although a very powerful weapon against targets of every caliber, this weapon is very rare without the Broken Steel add-on.
Inside Raven Rock there is a Gatling laser in an Enclave crate behind a blue energy shield as you are leaving Raven Rock, after you have spoken with President Eden. You will notice it on your right as you near the sentry bots which fight off three Enclave soldiers, just before the final door (leading to the Capital Wasteland). Deactivate the shield with the computer and you will find the Gatling Laser in one of the five crates.
Broken Steel - Gatling lasers are also carried by overlords. The overlords can be encountered from level 13 on.
Fawkes has one when he comes to aid you after exiting Raven Rock.
A Gatling laser may be carried or sold by a wasteland scavenger merchant spawned as part of the Type B random encounter where the scavenger is allied with a robot against a group of raiders. If the scavenger's Gatling laser is actively equipped, the scavenger can be forced to move the weapon to his merchant inventory by pickpocketing his ammunition for it, then fast traveling away and returning.