The heaviest class of combat robot in the United Statesmilitary, the sentry bot sacrifices speed and maneuverability for sheer resilience and overwhelming firepower. While the Assaultron is designed for melee combat and the Mister Gutsy is a jack-of-all-trades, the sentry bot's purpose is to engage the enemy at range with a variety of weapons, including miniguns, Gatling lasers, rocket launchers, and even back-mounted cluster grenade launchers, while its thick armor and multiple redundant systems allow it to survive extended engagements. It's commonly considered to be one of the most dangerous robots ever created and RobCo Industries' finest fighting robot. Late models are also provided with the ability to self-destruct to prevent enemy from recovering the robot. Early sentry bot models were issued serial numbers in the SB-#### format (model, then serial), with later models transitioning to the standardized alphanumeric registration in the ABC-###### format.
An early sentry bot model developed by RobCo Industries, designed specifically for heavy combat. The bot is divided into two halves, with the upper body containing the central processing unit, power core, and mounting the primary optical receptor. They are protected by a cast armored shell, consisting of just three pieces: The torso and upper assembly, a separate rear plate giving access to internal mechanics, and the head assembly protecting the main optical receptor. Its arms act as hardpoints, accepting a variety of weapons including miniguns, Gatling lasers, and rocket launchers. The lower body, connected by four shock absorbers and a centrally-mounted duct, contains fans venting accumulated hot air outside the chassis, preventing overheating. For movement, the lower body is fitted with three independent legs that provide it with a stable firing platform in any environment, much like a machine gun mount. The legs terminate in semi-spherical wheels (rubberized on the front, solid steel scoops on the back), giving it excellent mobility as well. Unlike the Gutsy or Assaultron, all sentry bots come with a simple synthetic personality.
Much like the Fallout 3sentry bots, those found in the Mojave wasteland boast a loadout comprising a minigun and a Gatling laser on the right arm, with a missile launcher on the left arm, complete with a high damage threshold that protects them against low damage weapons. Their head and legs take -50% and -25% damage respectively from all normal attacks. Its one flaw is the combat inhibitor mounted on the back and its slow turn rate, allowing the player to circle-strafe and destroy the inhibitor, causing it to frenzy (though it's pointless in areas without additional enemies). Pulse grenades, mines, and the pulse gun are effective countermeasures.
They are much less common in the Mojave than in the Capital Wasteland, though no less dangerous. They typically spawn in locations such as REPCONN Headquarters, Vault 11, or the Securitron vault. A special version is found at the crashed Vertibird, alongside hardened Mister Gutsies. These hardened sentry bots have 66% more health than regular sentry bots (500 vs. 300), but no damage threshold, making them more resistant to weapons that ignore it, such as pulse weapons, and more susceptible to regular weapons.
It is similar to the military sentry bot in appearance, but is differently colored. The NCR sentry bot was originally intended to be stationed in Camp McCarran, evident in its G.E.C.K. id McCarranFieldSentryBot, but was cut from the final version of Fallout: New Vegas.
↑Fallout 4 loading screen hints: "The Sentry Bot is one of the most dangerous combat drones ever created, and utilizes a variety of heavy weapons systems to destroy its enemies. Upon death, it erupts in a devastating explosion."
↑Serial numbers in Fallout 3 and Fallout: New Vegas.
↑REPCONN headquarters placard: ""Watch Your Step!"" "Whoa, watch your step! You don't want to be facing this fearsome fellow if you accidentally stumble into a restricted area. Whether sporting the latest in duel miniguns, rockets, or laser cannons, the Sentrybot not only takes it job seriously, it also takes no prisoners! It's proof of RobCo's commitment to defense that these deadly guards are concealed in chambers throughout this facility, so let this be a warning: Watch where you step, or out'll come RobCo, guns blazing!"
"Exhibit Brought to You By Your Friends at RobCo."
↑Tour guide: "Now for the highlight of our tour! Due to a generous donation from RobCo, this next exhibit showcases the wondrous world of - robots! Around you are the incredible Eyebot, the fearsome Sentry Bot, and the always-helpful Mr. Handy. That helpfulness runs through our whole line!This is the final stop on our tour. This model of our solar system is a small example of where the partnership between RobCo and REPCONN hopes to go.See those little rockets zipping about? They are manned by robots, tirelessly looking for resources to mine on planets beyond our own.And that's it for our tour today, Rocketeers - RobCo and its tiny partner REPCONN thank you! Any further questions, please, feel free to ask." (Tour guide's dialogue)