The Thermal Scope is used by Soap in "Cliffhanger". Thermal scopes are very useful in "Wolverines!" where enemies often use smoke grenades to hide themselves. Two M14 EBRs with thermal sights can be found on the roof of Nate's. Also, in "Loose Ends" one can obtain a WA2000 Thermal from a ghillie sniper or in the armory in the basement, and a F2000 Thermal can be taken from a ghillie sniper, regular Spetsnaz soldier, or in the mansion. There are also many PP-2000s and F2000s, and two Interventions, with thermal scopes during "The Only Easy Day... Was Yesterday", primarily when the enemies are shielding themselves with smoke grenades and even a few before that. A glitched dual TMP with thermal scope can be found in the campaign (The scope cannot be used). In Just Like Old Times, the Shadow Company popped smoke grenades and using thermal through the smoke but to counter them use a SCAR-H equipped thermal scope.
In multiplayer, the Thermal Scope features much more recoil and than the campaign and Special Ops version. When aiming down the sight, soldiers show up in solid white and everything else in a gray scale, unless they have the Cold-Blooded perk equipped, in which case they will show up in gray. However, teammates will show up white and will have flashing strobes on their bodies to make it known they are a friendly. Because it sees body temperature, the player using it can see enemy soldiers through smoke. The overall view through the sight is smaller than looking down a Sniper Scope or an ACOG Scope, but like a Sniper Scope, the player may steady their aim. This attachment doesn't work well on snowy maps as the snow will also show up white, (due to the small color gradient the developers used for the Thermal Scope having similar colors to the in-game snow's default color).
It is sometimes recommended that players using thermal scopes on snowy maps do not seek out high locations, so as to better see enemies in buildings. It is advisable for players to fire in bursts while aiming down the sight, since muzzle flash also appears white. Thermal, along with the ACOG Scope, slightly magnifies the heads of enemies, making it easier to get headshots, thus making it a popular scope for people attempting for prestigious camouflage such as the Fall Camouflage.
The Thermal Scope can be countered by the Cold-Blooded perk, but the player will not be completely invisible to the scope. The ordinarily white shape will simply appear in shades of gray, like the background. It should be noted that on snowy maps, the Cold-Blooded perk may make players more vulnerable to weapons with thermal scopes, as they would appear gray against the white snow.
The Thermal Scope returns in Call of Duty: Modern Warfare 3, and functions similarly to its Modern Warfare 2 equivalent. It also removes gun kick recoil, removing recoil on some weapons, such as L86 LSW. It is unlocked at Weapon Proficiency Level 19 for Sniper Rifles, Weapon Proficiency Level 26 for SMGs, Weapon Proficiency Level 27 for LMGs, and Weapon Proficiency Level 29 for Assault Rifles. It has a 2.4x zoom level when being aimed down, which is the same as the ACOG Scope, the Hybrid Sight with the magnifier on, and the AS50 standard zoom. As it was previously, the Thermal scope is capable of picking up targets not using Assassin through smoke produced from smoke grenades, as well as many other forms of visual hindrances caused by large explosions such as Predator Missiles. It is true however, that most dynamic environment is light, and therefore cannot be seen by the Thermal Scope. This renders that most non-static black objects are enemies with Assassin. Therefore, it is most effective on maps with dark color tones, such as Downturn or Lockdown. The Thermal Scope is also the only full-view scope for SMGs, LMGs, and Assault Rifles.
The Kick Proficiency helps with the recoil caused by the Thermal Scope. Grip is also useful for the Thermal Scope when using the Attachments proficiency on Light Machine Guns. The Thermal Scope is notably useful on the L86 LSW and MK46 because it reduces their high recoil to virtually zero recoil. The Thermal Scope is most effective on burst-fire weapons, such as the M16A4 and the Type 95, because the recoil settles after each burst.
The Thermal Scope will cut through smokescreen, rendering certain grenades useless, and highlights enemies without Assassin in white against a dark background. It also completely removes Gun Kick completely from all weapons, due to there being no gun model when ADS.
The Thermal Scope has the limited zoom of an ACOG, thus sniper rifles may benefit from a full-zoom magnification. One must hold his breath, requiring Marksman to properly maximise its advantages, and Assassin renders certain enemies immune to this. The ADS penalty is greater than the HAMR, demanding Quickdraw to avoid users being caught dead in mid-aiming. Only some maps, especially those with poor colour tones, will allow users to emphasise its strengths.
A third Person view of the Thermal Scope on an ACR 6.8.
A first Person view of the Thermal Scope on the ACR 6.8.
The Thermal Scope appears in Call of Duty: Advanced Warfare under the simplified name Thermal. Unlike previous variants of the sight, the sight now operates in color, showing enemies in red with a blue tint to the rest of the scope. It can be attached to assault rifles, submachine guns, sniper rifles (except the Atlas 20mm), and to the Pytaek, Ameli, Ohm and Crossbow. The sight itself is collapsed when not in use. When aiming, the screen slides open as the user brings the weapon up. Some killstreaks have a FLIR sight option, which appears to be identical to the Thermal sight's overlay.
The Thermal returns in Call of Duty: Black Ops III. The scope operates in color, as in Advanced Warfare, and has open peripheral vision. Unlike previous installments, the Thermal Sight reticle can now be customized with custom reticles.
"Identify enemies by detecting their increased heat signatures against the environment."
— Create-a-Class description.
The Thermal Scope returns in Call of Duty: Black Ops 4 as the NVIR. It operates with standard night vision colours while highlighting enemies in thermal imaging, unless they are equipped with Cold-Blooded where they do not become highlighted.