AKS-74u

The M92 Krinkov is a Yugoslavian copy of the AKS-74u, a Russian compact assault rifle created in the Soviet Union in the 1980s. It was designed to be used by pilots, tank crews and other echelons of the Soviet Army where a full-sized rifle was impractical for defense, but the power of a full-sized rifle round was required. The AKS-74u is chambered in 5.45x39mm, the same as the AK-74 from which it is derived. The AKS-74u is still used in Russia by front line troops. The AKS-74u is still used by other former Eastern Bloc countries, former Soviet Union-affiliated states, and sometimes by insurgent groups. The most infamous example of the later is Osama bin Laden, as one is frequently seen with or around him in his video addresses. Nicknames for the AKS-74u include Krinkov in English speaking countries and  Ksyusha in Russian-speaking countries. For some reason, the Create-a Class model has a Picatinny Rail on the foregrip, which is absent in game.

In Game
In Call of Duty 4: Modern Warfare, the AKS-74u is incorrectly considered a submachine gun. The weapon is named correctly, although the AKS-74u has a side folding stock like shown in the reference, while the AK-74u has an underfolding stock. It is first found on the level Crew Expendable and seen semi-commonly throughout the game being used by the Russian Loyalists, Ultranationalists, the Middle-Eastern OpFor, and Nikolai once he is rescued in Blackout and during the subsequent level, Hunted.

In multiplayer, the AKS-74u can be customized with a red dot sight, suppressor and ACOG scope. This weapon is fairly similar to the MP5, in that both weapons have the same damage, rate of fire, and range. Otherwise, they are different. In Core game modes when not using a Suppressor, the AKS-74u is statistically the best submachine gun in the game. This is not conjecture. It is tied with the MP5 in terms of damage output, but it has less recoil and much better wall penetration at the cost of slightly lower movement speed, more idle sway, and worse hip accuracy when using a red dot sight.

The AKS-74u bears many similarities to weapons in the assault rifle class. It is the only sub machine gun with noticeable sway (4 degrees, and it sways quickly, the same amount and speed as the AK-47), and it also has the same wall penetration as assault rifles, light machine guns, and sniper rifles. Also, its hip-fire accuracy is reduced to that of an assault rifle when equipped with a red dot sight or suppressor, which are the two most popular attachments. It also has the same mobility as an assault rifle. The AKS-74u is only similar to other SMGs in its movement speed during ADS, its damage decay over range, and its hip-fire accuracy when using no attachment or an ACOG.

Some other interesting stats are that its sway is reduced by crouching and going prone, and its hip spread is greatly reduced by crouching, more so than other guns.

Trivia
The serial number of AKS-74u is R060479. It can be seen when holding the gun.

The gun's magazine is too curved for AK-74 magazines, yet it is unknown if the 5.45x39 mm rounds would fit into the magazine despite being a bottle-necked 7.62x39mm

The model in-game is actually based on AK-47 "Beta Spetsnaz",an AK airsoft gun model made by Tokyo Marui,as evident with the gas tube, which is too short even for an AKS-74U and the AK family. The real-life version features a side folding stock.

In the armory during the mission F.N.G, there is an AKS-74u with a grenade launcher attached, which is not available or seen anywhere else in the game.