Duplet

"The 12-gauge shotgun is one of the best close combat weapons ever. A blast from both of its barrels can kill almost any mutant on the spot."

- In-game description

Also known as the Double-Barreled Shotgun, the Duplet (Russian: Дуплет) is a scratch-built double-barreled shotgun crafted in the metro. It has two barrels with one shotgun shell in each. While this system has considerable drawbacks, including a very limited ammo capacity, the Duplet is capable of causing more concentrated damage at close range than any other gun and remains a powerful and respectable weapon because of this.

Tactics and Use
The Duplet, like the Bastard gun, is a poor gun on paper. It holds very little ammunition, has an extremely wide scatter pattern, and a sluggish reload (though still better than several other guns, including the Uboinik, which takes considerably longer to be fully loaded). What these statistics fail to take into consideration is that the Duplet possesses the single highest primary-fire damage in the game; firing both barrels up close will one-shot kill any enemy shy of a demon, librarian, or plated nosalis, given a head-shot (these enemies all require considerably more firepower regardless). When playing on the Ranger difficulties the Duplet can be an extremely effective weapon, not only because of its availability, but because it's firepower is enough to kill a nosalis or lurker in one shot at point-blank range.

The Duplet's basic use is not a complex one: Get in close, give both barrels, either sequentially or at the same time - but in practice, it is much harder to make full use of.

It's extremely easy to miss cagier and evasive targets, especially at closer ranges where the spread pattern is tighter - where it also does the most damage. Because of its long reload time between shots, it is extremely easy to wind up in a position where you are caught with empty chambers in a firefight, and thus in particular danger when fighting down enemy opposition, especially when the mutants are at your face.

It is by no means a bad weapon, and can indeed be used throughout all of the game without suffering from the change of pace, but many prefer the Uboinik due to its greater ammo capacity and added melee capability (not available for Metro: Last Light), both of which make the Uboinik considerably easier to use and more lethal than the Duplet - even if it lacks the Duplet's raw punch from both barrels. The Uboinik also has a considerably tighter spread, meaning it maintains its lethality over longer ranges, whereas the Duplet's damage drops dramatically beyond close-range. In Last Light, the player who use shotguns a lot may prefer the Saiga as its superior to the others in many ways, or Abzats, although not everyone can obtain it.

Metro: Last Light
In Metro: Last Light, the Duplet is the second shotgun available to Artyom, after the single-shot Ashot, and appears early in the game. The Duplet is considered a better choice than the Ashot in nearly all situations due to a holding capacity of two shotgun rounds that reload quickly, rather than one. As in Metro 2033, the Duplet suffers from a small capacity. Despite its improvements and mods, the weapon is not a strong choice to play through most of Last Light with, as frequent reload in hot situations may prove dangerous. Players that prefer to use shotguns may consider replacing their Duplet early on with Shambler, Saiga, or even the Abzats. The player looking for the maximum close range firepower in one blast may consider this weapon as it can shoot four rounds in an instant via weapon attachment.

Variants and Customization
The Duplet can equip six different attachments that come in two attachment slots. Duplet has two unique upgrades not found on any other weapon - the Ergonomic grip, and a "Four Barrels" upgrade, which lets the player fire either two or four shots at once.

Metro Exodus
The Duplet doesn't entirely return in Metro Exodus, but a similar weapon can be mocked up by modifying an Ashot with the Double Barrel upgrade. This weapon lacks the two-shot firing mode of the proper Duplet, however, but can be aimed.

It does, however, make a quick cameo appearance in Sam's Story. The Captain, upon meeting him for the second time, wields it against a Humanimal who is attacking him from a window, but the weapon jams and fails to fire. After Sam killed the mutant with an axe, it came tumbling out of said window and taking the Duplet with it.

Trivia

 * It is possible that the "Old School" achievement associated with the Duplet is a reference to the DOOM series of FPS games, specifically the double-barrelled "Super Shotgun" from that game series.
 * If left idle for an extended period with it equipped, Artyom will adjust the stock, pull it back too far, and then carefully slot it back into place.
 * There is a rare glitch where pulling the trigger causes the shotgun to recoil, but there is no sound and the round is not fired. Although it doesn't actually fire, the weapon still uses one shell.
 * The weapon is similar to home-made weapons built during the Siege of Sarajevo during the Bosnian Wars, with at least one pattern of ersatz shotgun built of gas pipe bearing a close resemblance to the Duplet.
 * The Duplet actually has an aiming bead. It is not usable in any of the Metro games however.
 * The Duplet's reload animation shows Artyom pull the barrels further down after pressing on the hinge release, which causes spent shells to eject on their own, even though the weapon itself doesn't appear to have a functional extractor.

Metro: Last Light

 * Due to the stock being an attachment and not on the Duplet by default in Metro: Last Light, there is a new idle animation where Artyom releases the barrels but gets his finger stuck between the hinge of the barrels and the frame of the gun, causing him to grunt in pain and look at his sore finger before locking the gun.
 * Metro: Last Light features a new reload animation. Artyom can load both barrels at once, as opposed to one-at-a-time method from Metro 2033. The new reload animation also applies to Metro 2033 Redux.
 * According to a rep for 4A Games, Artyom has been through a lot. Therefore in Metro: Last Light, Artyom's quicker reloading is because of his experience gained with weapons and refining the combat skills he obtained in Metro 2033.
 * He can also reload all four barrels of a four-barrelled Duplet at once. Although not impossible, it would be very difficult to load all four shells correctly.
 * A modded variant of the Duplet with four barrels can be obtained. The first one can be found in the "Bandits" level atop the walkway before signaling Fedor. The second one can be found on the level Undercity, on a body. And another can be found near one of the bodies in the Red Square level where the fight with Pavel occurs.
 * The four-barrel blast would make the Duplet the most powerful shotgun in terms of the individual shot.
 * The stock from Metro 2033 is removed in Metro: Last Light and in Metro 2033 Redux, and a new stock is added as purchasable upgrade.
 * During some cutscenes where Artyom is shown from a third-person perspective, he can be seen with a default Duplet.
 * During Artyom's journey to Oktyabrskaya, he can find a Duplet with no grip on a backpack next to a corpse. This happen every playthrough regardless of whether the player encountered a bug or not.

Metro Exodus

 * When Sam meets the Captain for the second time in Sam's Story, he can be seen trying to fight off a humanimal that is crawling through his window with a Duplet, which fails to fire. The humanimal then takes the Duplet with it when it's killed by Sam and tumbles back out the window into the water below. The Captain refers to it as his "rifle", despite it being clearly a shotgun.

Gallery
Duplet Дуплет Дуплет