Sentry Gun

“

How am I going to stop some big mean mother hubbard from tearing me a structurally superfluous new behind? The answer: use a gun. And if that don't work... use more gun. Click to listen — The Engineer (Meet the Engineer)

”

The Sentry Gun (abbreviated to SG), officially known as the Sentry Mechanical Firing Device, and also as a Sentry or Turret, is a building that can be constructed by the Engineer using the PDA, the Engineer's build tool. The gun itself is a tripodal device constructed of metal, team-colored paint, and a laser sight (when used with the Wrangler).

A level one Sentry Gun is a single-barrel machine gun with an internal magazine. The Sentry has a motion sensor, as stated in Meet the Engineer and the Sentry Manual.

A level two Sentry Gun appears to use an automatic cranking system to rotate the barrel, as indicated by the 2 electric cables visible. It also has 2 Gatling guns and a laser sight is built into the carbine body. Its ammunition is belt-fed.

A level three Sentry Gun is identical to the level two, with the exception of an additional set of rocket silos on the top, which comes out of the back ammunition housing area.

The Sentry Gun functions as an automated turret that fires at the closest enemy within its range and line of sight. Dealing constant as well as consistent damage with noticeable knockback and an immunity to critical hits, a Sentry Gun is the cornerstone of a successful defensive setup. On the other hand, they take a while to set up to full potential, and even a fully-stocked Sentry Gun can be destroyed with little trouble by a well-executed ÜberCharge or a Spy with his Sapper. Engineers must be on the lookout for such threats to ensure their Sentry Gun's survival. If a Sentry Gun is sapped, it gains a 33% damage resistance against a Spy's weapons.

Functionality

General

The Sentry Gun costs 130 Metal to build, 200 Metal to upgrade to Level 2, and an additional 200 to upgrade to the third and final level totaling to 530 Metal. With each upgrade level, the Sentry Gun becomes more powerful, gaining machine guns, rockets, as well as more health. The firing range remains constant regardless of level. The Sentry Gun's ammo and health may be replenished with Metal by the Engineer hitting it with his melee weapon. Each bullet reloaded costs 1 Metal and each rocket reloaded costs 2 Metal.

When placing a Sentry Gun, the Engineer can see the limit of its range represented by a team-colored sphere of 1100 Hammer unit radius. A Sentry Gun that is being constructed has health increase gradually until it reaches its maximum health upon completion. While automatically scanning, the Sentry Gun rotates 90 degrees about the direction it is pointing; however, it is capable of detecting and rotating the full 360 degrees to lock on to a target. This takes a brief moment, however, which may allow faster foes to slip past its range. The Sentry Gun can also be manually rotated when placing to face a different direction before building commences. When the blueprint is shown, using the alt-fire button (default key: MOUSE2) rotates the blueprints counter-clockwise by 90 degrees.

Properties

As do other Buildings, Sentry Guns emit sound cues to alert players to their presence and status. A scanning Sentry Gun makes a number of beeps every time it reverses its rotation (1, 2 3) — the number of beeps corresponds to its upgrade level, where a Level 3 turret makes three quick beeps. Additionally, this beeping increases somewhat in volume with Level 2 then Level 3 Sentry Gun's level; so, the higher the level, the farther away the Sentry Gun can be heard; this fact can help attentive players find guarded areas. The Sentry Gun's scanning noise sounds slightly different when being fired on by the enemy; slight clicks can be heard along with the regular beeps. The scanning Sentry Gun also makes a distinctive noise when it detects and locks onto an enemy target just before firing — this noise both alerts the enemy of the detection by the Sentry Gun and the team of the presence of an enemy within the range of the Sentry Gun. Enemies detected by a Sentry Gun hear its noise as a slightly different alert noise. All of these scanning noises are silenced when a Sentry Gun is Wrangled.

A Sentry Gun constantly checks if there is an enemy player or building in scanning range with a clear line of sight. If multiple targets meet this criteria, it selects the closest one and switches targets the instant another target is closer. Sentry Guns also only attempt to fire once they have lined up with the target, even if firing before then could cause damage to an enemy. Sentry Guns have a maximum rotation and pitching speed when attempting to track a target, which increases with level and is faster than its idle scanning rotation. Sentry Guns still aim and try to fire at enemies even if their ammo reserves are empty.

Sentry Guns cannot see through geometry and Engineer buildings, however they ignore friendly players.

After running out of valid targets for whatever reason, the Sentry Gun briefly stays pointing in the direction of its last detected target before returning to its scanning sweeps.

Since the Engineer Update, players are able to haul their buildings around. An Engineer carrying his Sentry Gun moves 10% slower and cannot fire or change weapons. A redeployed Sentry Gun retains its previous level and automatically sets up twice as fast. Engineers do not lose any Ammo or Metal by moving Sentry Guns (unless the Sentry Gun was picked up with the Rescue Ranger's alt-fire, which costs 100 metal for moving any building). If the Engineer is killed while hauling his Sentry Gun, it is automatically destroyed along with him and gives a notification in the kill icon area of the screen. Sentry Guns under the effects of a Sapper cannot be picked up.

Like most other weapons, the Sentry Gun's weapons have damage ramp-up and fall-off. Sentry Gun bullet ramp-up and fall-off is calculated based on the distance between the enemy and the Sentry Gun. However, the rockets from a Level 3 Sentry Gun calculate their ramp-up and fall-off based on the distance between the enemy and the Engineer who built the Sentry Gun.

Unlike most other weapons, the Sentry Gun's weapons do not gain critical hits. It is possible, however, to make the Sentry Gun deal mini-crit attacks and damage if its target is coated in Jarate, being Marked For Death, or if the Engineer who built the Sentry Gun is close to a Soldier with an active Buff Banner – boosting the damage of each bullet to 22.

Sentry Guns are controlled by the TF2 server rather than the Engineer's client. That means Sentry Guns behave the same regardless of the connection quality of the Engineer that built them.

Specific properties

Included in the Engineer Update as an unlockable secondary replacement, the Wrangler allows the Engineer to take direct control of his Sentry Gun by "marking" targets manually. Doing so shuts down the Sentry Gun's automated target-lock system, but diverts the excess power from the targeting system into speeding up its firing rate, effectively doubling the damage-per-second of the Sentry Gun. The Wrangler also provides the Sentry Gun with a protective shield which absorbs two-thirds of enemy fire while the Wrangler is active. A wrangled Sentry Gun has no maximum range, though its accuracy slightly decreases at longer ranges and its knockback force is halved against targets outside of its normal reach. Once the Engineer switches away from the Wrangler, however, his Sentry Gun is unable to fire for 3 seconds while its auto-lock targeting computer reboots. It is still shielded during this time.

In Mann vs. Machine, Sentry Guns can gain benefits from certain Power Up Canteens their owners use. An ÜberCharge Canteen forms a Wrangler-esque shield around the Sentry Gun, reducing incoming damage by 90%. Use of a Kritz Canteen triples the Sentry Gun's firing rate. An Upgrade Buildings Canteen instantly upgrades the Sentry to Level 3 as well as fully repair it, however it does not refill the Sentry Gun's ammo. Sentry Guns can also be upgraded at Upgrade Stations to increase their health and firing rate, and the Engineer can even buy a Disposable Sentry Gun, allowing him to place a second Mini-Sentry that is slightly worse than a Combat Mini-Sentry.

Vulnerabilities

Sentry Guns are damaged by most weapon effects that damage players; however, some effects are modified for Sentry Guns. Also, weapon damage done to a Sentry Gun does not suffer from range falloff, with the exception of any scatter-based weapon. A destroyed Sentry Gun drops 65 Metal worth of scrap pieces, which can also be picked up by other classes as Ammo.

Sentry Guns do not fire upon enemy Spies that are cloaked. In general, Sentry Guns do not fire upon enemy Spies that are disguised; however, if the Sentry was firing upon the Spy at the time the disguise was activated, it continues to fire upon the Spy until the Spy cloaks, breaks line of sight, or moves out of range. Sentry Guns also do not fire upon enemies in its range if there is a water surface between them or if the enemy is behind cover – this cover includes the Engineer's Dispenser. Sentry Guns are also unable to fire if an enemy Spy attaches a Sapper to it or while they are being upgraded/built. Feign deaths produced by the Dead Ringer are not added to the Sentry Gun kill/assist counter, but do contribute to the Best Little Slaughterhouse in Texas achievement.

An Engineer is vulnerable to damage from his own Sentry Gun's bullets. For about the first 300 Hammer units of their flight, Sentry Gun rockets pass through the Sentry Gun's Engineer without detonating as if he were another member of the same team. However, if the rockets do strike another surface within this distance and explode, the Engineer is vulnerable to the resulting splash damage. Beyond this initial distance, the Engineer is fully vulnerable to his own Sentry Gun's rockets (the knockback from Sentry Gun self-damage enables the Engineer to perform bullet and Sentry rocket jumps, especially with the aid of the Wrangler).

Metal spending priority

When an Engineer hits a Sentry Gun with their melee weapon, the metal is spent in a certain order:

1. Health
2. Upgrade Progress
3. Ammo
   1. Bullets
   2. Rockets

However, Ammo is usually filled alongside Health and the Sentry Gun's Upgrade Progress. When Ammo is being filled, the bullets for the Sentry Gun are filled first, then the Sentry Rockets are filled.

Combat Mini-Sentry Gun

“

Ain't that a cute little gun? Click to listen — The Engineer on his Combat Mini-Sentry Gun

”

The Combat Mini-Sentry Gun, also known as Mini-Sentry or simply Mini, is a more combat-efficient version of the standard Sentry Gun and is a component of the Engineer's Gunslinger unlock. It is a smaller Level 1 Sentry Gun outfitted with a rotating light that glows and is painted with a white checkered paint. Like the Sentry Gun, it can be hauled.

Advantages

• Costs only 100 Metal to place (the normal Sentry costs 130 Metal). This allows an Engineer at a full 200 Metal to build both it and a Dispenser without needing additional Metal.
• Constructs much faster than the original Sentry Gun. Hitting the Sentry makes it construct faster and, when deployed after hauling, it is armed in 1.5 seconds.
• Cheap and disposable means of area denial.
• Begins construction with 50 health. This makes the Mini-Sentry less vulnerable while under construction when compared to the default Sentry Gun, which begins construction with 1 health.
• Fires 25% faster than a Level 1 Sentry Gun.
• Can rotate 35% faster than the default Sentry Gun.
• 75% the size of a regular Sentry Gun, making it harder to notice and hit.
• More useful for Sentry jumping, as the firing rate and reduced damage combine to deal more knockback for an equivalent health loss.

Disadvantages

• Has only 100 health, compared to a Level 1 Sentry Gun's 150.
• Cannot be upgraded. The owner and other Engineers can still refill its ammo and health.
• Deals only 50% the damage per shot of the original Level 1 Sentry Gun. Combined with the 25% faster firing rate, the damage per second is overall 38% lower (~50 DPS compared to the Level 1 Sentry Gun's ~80 DPS).
• Bullets apply significantly less knockback force (800% knockback multiplier compared to a regular Sentry Gun's 1600% multiplier).
• Drops zero Metal when destroyed.
• Once a Sentry jump is executed, not exceptionally useful as part of a base in the new area.

Disposable Mini-Sentry

In Mann vs. Machine, the Engineer can buy a Disposable Sentry that at first glance just looks like a normal Combat Mini-Sentry Gun, however there are a few differences:

• Has a slower firing speed than a normal Mini-Sentry.
• Cannot be repaired or have its ammo refilled.
• Cannot be destroyed by the Engineer who made it - it can only be destroyed by an enemy robot or a Tank if it's placed on its path.
  • Outside damage sources, the disposable will also be automatically destroyed when a wave is finished or when it runs out of ammo.
• Cannot be wrangled, but still receives canteen buffs.
• Is 66% the size of a normal sentry compared to the Combat Mini-Sentry's 75%.
• Is not affected by the building health upgrade (always has 100 max health).
  • However, it is affected by the Sentry Firing Speed upgrade.

Sentry Gun Levels

Level	Kill icon	Health	Cost (Metal)	Weaponry	Damage	Ammo
1		Without Wrangler shielding: 150 With Wrangler shielding: 450	130	Single barrel machine gun	Damage Maximum ramp-up: 19.49 Base damage: 16 Maximum fall-off: 8.45 Attack interval Without Wrangler: 0.225 seconds With Wrangler: 0.135 seconds Average DPS Without Wrangler: 71.11 - 84.44 With Wrangler: 118.52 - 140.74	150 rounds
2		Without Wrangler shielding: 180 With Wrangler shielding: 540	330	Twin-mounted Gatling guns	Damage Maximum ramp-up: 19.49 Base damage: 16 Maximum fall-off: 8.45 Attack interval Without Wrangler: 0.135 seconds With Wrangler: 0.09 seconds Average DPS Without Wrangler: 118.51 - 140.74 With Wrangler: 177.78 - 211.11	200 rounds
3		Without Wrangler shielding: 216 With Wrangler shielding: 648	530	Twin-mounted Gatling guns and rocket salvos	Gatling guns Damage Maximum ramp-up: 19.49 Base damage: 16 Maximum fall-off: 8.45 Attack interval Without Wrangler: 0.135 seconds With Wrangler: 0.09 seconds Average DPS Without Wrangler: 118.51 - 140.74 With Wrangler: 177.78 - 211.11 Rockets Damage Maximum ramp-up: 150 Base damage: 100 Maximum fall-off: 52.81 Falloff is calculated from the distance of the Engineer to the target, not from the Sentry to the target Attack interval Without Wrangler: 3.06 seconds With Wrangler: 2.25 seconds Note: Can be reflected with the Pyro's compression blast	200 rounds 20 rocket salvos
Combat Mini-Sentry Gun		Without Wrangler shielding: 100 With Wrangler shielding: 300	100	Single barrel machine gun	Damage Maximum ramp-up: 9.74 Base damage: 8 Maximum fall-off: 4.22 Attack interval Without Wrangler: 0.18 seconds With Wrangler: 0.09 seconds Average DPS Without Wrangler: 44.44 - 55.56 With Wrangler: 88.89 - 111.11	150 rounds
Disposable Sentry Gun		100	Without Gunslinger: 130 With Gunslinger: 100	Single barrel machine gun	Damage Maximum ramp-up: 9.74 Base damage: 8 Maximum fall-off: 4.22 Attack interval: 0.225 seconds Average DPS: 35.56 - 42.22 Note: Only available in Mann vs. Machine as an upgrade and cannot be wrangled, repaired, or have its ammo refilled.	150 rounds

Advanced Tactics

• Sentry Jumping

Related achievements

General achievements

Sentry Gunner Accumulate 10 sentry gun kills with a single sentry.

 Scout

Gun Down Destroy an active sentry gun using your pistol.

 Soldier

Engineer to Eternity Kill an Engineer as he repairs his sentry gun while it's under enemy fire.

Guns of the Navar0wned Kill 5 Engineer Sentry Guns while you are standing outside of their range.

 Demoman

The Argyle Sap Blow up an Engineer, his sentry gun, and his dispenser with a single stickybomb detonation.

 Engineer

Best Little Slaughterhouse in Texas Rack up 5000 kills with your sentry guns. Breaking Morant Kill 10 Snipers with a sentry gun under the control of your Wrangler. Building Block Have a sentry shielded by the Wrangler absorb 500 damage without being destroyed. Deputized Get 10 assists with another Engineer where a sentry gun was involved in the kill. Doc, Stock, and Barrel Repair a sentry gun under fire while being healed by a Medic. Frontier Justice Have your sentry kill the enemy that just killed you within 10 seconds. If You Build It, They Will Die Haul a level 3 sentry gun into a position that achieves a kill shortly after being redeployed. No Man's Land Use a sentry gun to kill 25 enemy players that are capturing a point.

Patent Protection Destroy an enemy Engineer's sentry gun with a sentry under control of your Wrangler. Pownd on the Range Kill 10 enemies outside the normal sentry gun range using the Wrangler. Revengineering Use a revenge crit to kill the enemy player that destroyed your sentry gun. Rio Grind Perform 50 repairs and/or reloads on a Sentry gun being Wrangled by another Engineer. Search Engine Kill 3 cloaked Spies with a sentry gun under control of your Wrangler. Texas Two-Step Use your shotgun to finish off an enemy recently damaged by your sentry gun. Uncivil Engineer Provide an enemy player with a freeze cam of you and the sentry that just killed them.

 Medic

Midwife Crisis Heal an Engineer as he repairs his sentry gun while it's under enemy fire.

 Sniper

De-sentry-lized Destroy 3 Engineer sentry guns.

 Spy

Constructus Interruptus Kill an Engineer who is working on a sentry gun.

Joint Operation Sap an enemy sentry gun within 3 seconds of a teammate sapping another.

Mann vs. Machievements

Real Steal As an Engineer, escape with your sentry as a sentry buster is about to detonate.

Undelete During a wave, use a canteen charged with 'Instant Building Upgrade' to build a new sentry gun within 3 seconds of your previous sentry gun's destruction.

Update history

September 20, 2007 Patch

• Fixed Sentry muzzleflashes not drawing unless sentry was near the map origin.

October 25, 2007 Patch

• Engineer buildings now explode when the Engineer dies during sudden death.

November 7, 2007 Patch

• Fixed a bug in scoring Engineer building destruction.

December 20, 2007 Patch

• Sapped buildings now take slightly less damage from the Spy who sapped them.
• [Undocumented] Fixed model exploit in stage one allowing Sentry Gun/Teleporter to be placed behind chain link fence on Dustbowl.

February 14, 2008 Patch

• Added server log entry for buildings destroyed by their owner.
• Fixed Sentry Gun shadows being clipped.

February 28, 2008 Patch

• [Undocumented] Changed Engineer buildings to detonate when a player disconnects instead of blinking out.
• [Undocumented] Fixed Engineer being able to detonate buildings that are being sapped.

April 29, 2008 Patch (Gold Rush Update)

• Mapmakers can now place Engineer buildings directly into a map, with an option for them to be invulnerable.

August 13, 2009 Patch

• Fixed Sentry Guns firing at a fully cloaked Spy if they're still the closest target.

April 28, 2010 Patch

• Killing yourself with your own Sentry Gun no longer increments the Sentry Gun's kill counter.

April 30, 2010 Patch

• Fixed the Engineer being able to build more than 1 of each type of building.

July 8, 2010 Patch (Engineer Update)

• Added the ability to haul or move your Sentry Gun, along with having the Wrangler control the Sentry Gun
• Added a laser light to all sentry models.
• [Undocumented] 'Wrenching' a Sentry Gun now upgrades, repairs and restores ammunition all at once per Wrench hit, prioritizing repairs and upgrading if not in possession of enough metal.

July 9, 2010 Patch

• Fixed an exploit that allowed Engineers to build level 2 or 3 mini Sentry Guns.

July 13, 2010 Patch

• Fixed an exploit where Engineers could create level 3 mini-Sentry Guns.

July 19, 2010 Patch

• Fixed an exploit that allowed team kills with Wrangled Sentry Guns.

October 18, 2010 Patch

• Fixed a Sentry Gun exploit that let Engineers build multiple Sentry Guns.
• (Supposedly) Fixed Engineers being able to build level 3 mini-Sentry Guns using the Wrangler.

October 19, 2010 Patch

• Fixed another Sentry Gun exploit that let Engineers build multiple Sentry Guns.
• Fixed Engineers being able to build level 3 mini-Sentry Guns using the Wrangler (for real this time).

December 17, 2010 Patch (Australian Christmas)

• Sentry Guns no longer track Your Eternal Reward Spies after they backstab someone.

January 7, 2011 Patch

• Updated Sentry kill icons.

January 10, 2011 Patch

• Combat Mini-Sentry is given a kill icon.

January 19, 2011 Patch

• Fixed the mini-sentry HUD not playing the alert sound when the sentry is sapped or low on ammo.

February 3, 2011 Patch

• Engineers who hit teammate's Sentry Guns with their Wrench now get kill assists from that Sentry Gun.

March 10, 2011 Patch (Shogun Pack)

• Fixed the "Best Little Slaughterhouse in Texas" Engineer achievement not counting Wrangler and Mini-Sentry kills.

May 5, 2011 Patch (Replay Update)

• [Undocumented] Sentry Guns now properly target the Horseless Headless Horsemann as an enemy.

April 17, 2012 Patch

• Fixed being able to place buildings in nobuild zones.

June 27, 2012 Patch (Pyromania Update)

• Fixed sentry sometimes spawning in shielded mode while the Wrangler was equipped, but not deployed.

August 10, 2012 Patch

• Fixed Sentry Gun sometimes placing wrong, being rotated into the ground and pointing upward.

March 19, 2013 Patch

• Fixed a bug where Sentry Guns would not rotate to face their target under some circumstances.

May 13, 2013 Patch

• Fixed a bug that allowed level 3 mini-Sentry Guns in Mann Vs. Machine mode.

February 7, 2014 Patch

• Fixed the Mini-Sentry range-sphere not accurately displaying the range for the sentry when it is being placed.
• Fixed a UV/skinning problem on the level 1 Sentry Gun.

May 15, 2014 Patch

• Fixed a bug that would cause the Sentry Gun’s health to look overhealed when it wasn’t.

June 18, 2014 Patch

• Sentry bullets are now affected by damage falloff outside of sentry scan range.
• Sentry bullet damage has been changed so it calculates damage based on the Sentry Gun's position, not the Engineer's.

September 10, 2014 Patch

• Fixed Mini-Sentry collision hull and hitbox being scaled smaller than they should be.

January 7, 2015 Patch

• Added enemy team func_nobuild volumes to the capture zone areas in ctf_foundry and ctf_gorge to prevent spawn-camping Sentry Guns.

July 23, 2015 Patch #1

• Fixed Sentry Guns shooting over the head of Spies using the Box Trot taunt.

July 23, 2015 Patch #2

• Fixed Sentry Guns having unlimited ammo.
• Fixed Sentry Gun model being set to level 1 after a Sapper is removed.

December 17, 2015 Patch (Tough Break Update)

• After removing a Sapper from a Sentry Gun, there is now a 0.5s delay before the sentry is active again.
• Sentry Guns brought into a respawn room no longer detonate outside of Mann vs. Machine.

December 18, 2015 Patch

• Fixed a bug with Sentry Guns being disabled for 5 seconds instead of the desired 0.5 seconds after a Sapper is removed.

August 29, 2016 Patch

• Fixed mini-Sentry Guns not having full health when they are built quickly during the setup time on Mann vs. Machine maps.

May 1, 2020 Patch

• Fixed an exploit where Sentry Guns could fire through thin walls.

July 7, 2022 Patch

• Fixed Mini-Sentry Guns not triggering damage alerts in the HUD

Bugs

• The player has the ability to build the Combat Mini-Sentry Gun, while having any wrench equipped, by holding out the blueprints for the Sentry with the Gunslinger and then quickly switching to a wrench. The player builds a Mini-Sentry (it still costs 130 Metal). This cannot be done vice versa (equipping the Gunslinger while having normal Sentry blueprints out). If this is done with the Jag the Sentry gets the construction boost effect.
• Sometimes, when an upgraded Sentry is moved, it fires a bullet between upgrade stages if pointed directly at an enemy or Wrangled.
• Rarely, after removing a Sapper, all of the Sentry Gun's ammunition, including rockets, is completely gone.
• A Wrangled Sentry does not play its rocket-reloading animation.
• Wrangling a Combat Mini-Sentry Gun might result in it remaining in the Wrangled state even when the Wrangler is not the currently active weapon.
  • Switching back to the Wrangler corrects the problem.
• After the Mini-Sentry finishes its building animation, it sinks into the ground slightly.
• Occasionally, after being built, a Level 1 Sentry might be frozen in animation and not fire any bullets.
• There still exists a way to get a Leveled Mini-Sentry on some custom maps.
• Sometimes, when a Spy saps the Sentry Gun during it being constructed, the Engineer can not destroy the Sapper, making him have to destroy the Sentry Gun, or let the Sapper destroy the Sentry Gun.
• Rarely, when a Sentry Gun has been sapped and the Engineer has changed class or left the game, the Sapper appears floating in the air.
• The damage of the Sentry Gun's rockets is calculated based on the distance between the enemy and the Engineer, not the Sentry Gun. Therefore, if the Engineer is closer to the enemy being targeted by the Sentry Gun, it does more damage.
• When mini-crit boosted, the Sentry Gun's damage can be seen through walls, when normally you cannot.

Unused content

• An unused alternate kill icon for the Level 1 Sentry Gun exists in the game files.

Trivia

• Radigan Conagher created modern Sentry Gun designs by 1890. The 1890 and current designs are visually identical.
  • Radigan Conagher's notes suggest an earlier steam-powered Sentry Gun design.
• Valve ordered and received a full size motion-tracking model of a Level 1 Sentry Gun from Weta Workshop.
• Clicking "View the manual" button on the Steam store page of Team Fortress 2 opens an online PDF file of the Sentry Operating Manual.
  • The Sentry Operating Manual uses the recycling symbol to tell players they can reuse metal from destroyed equipment. However, that the sign was not created until 1970.
  • The cover of the Sentry Operating itself is more like that of the late 1950s to early 1960s, whereas the game itself takes place in July of 1968 (The Calendars). By that point, the font of "Sentry" was outdated and was no longer being used. Industrial (upon which the game is heavily based) used a very basic font even before that.
  • The Sentry Operating Manual is in color, which would be wrong for an industrial manual as most are not in color, especially during the 20th century.
• On the back of the Level 3 Sentry Gun's rocket salvo, a tab connects three of the four rockets to the device.
• In Payday 2, on a train robbery mission, the robbers steal a Level 1 Sentry Gun.

Gallery

Sentry Gun levels

• 

  Level 1 Sentry Gun.

• 

  Level 2 Sentry Gun.

• 

  Level 3 Sentry Gun.

• 

  Combat Mini-Sentry Gun.

• 

  Build to Level 3 animation.

Development

• 

  Sentry Gun concept art.

• 

  Sentry Gun concept art.

• 

  Sentry Gun explosion.

• 

  Sentry Gun concept art.

• 

  Sentry Gun models with ambient occlusion.

Storyline

The Storyline was expanded within the Engineer Update. From Loose Canon, the Sentry Gun Manual, and the Engineer Update Page, it is inferred that Radigan had developed the modern Sentry design before exposure to Australium and that the Engineer obtained the Sentry plans in the early 1960s from his Grandfather's notes.

• 

  Radigan's steam-powered Sentry design.

• 

  Radigan's 1890s advanced Sentry design.

Sentry Gun Operating Manual

• 

  Front Cover.

• 

  Page 2.

• 

  Page 3. Sentry Gun Components.

• 

  Pages 4-5. Modifying your Sentry.

• 

  Back Cover.

Other images

• 

  Icon for a hauled item being destroyed via the Engineer's death.

• 

  Unused Sentry kill icon.

Merchandise

Main article: Merchandise

• 

  Sentry Mousepad

• 

  Sentry Poster

See also

• Basic Engineer strategy
• Sentry Gun placement

External links

• Sentry Operating Manual