While the game is not primarily a shooter, guns play a major role in Syndicate. Although not the first Assassin's Creed game to have guns, it is the first to feature them as a major tool of combat. The player can only carry available handguns, most of which are revolvers. There are also some single-shot, break-barrel, and self-loading guns as well.
Colt 2nd Model Derringer
Henry Greene gives the Frye's their own Colt 2nd Model Derringer in one of the earliest missions. In the game's menu it is simpley referred to as the "Derringer Pistol". This is slightly anachronistic with the the Colt 2nd Model Derringer not being produced until 1870, however its precursor the National Arms Co. 2nd model Derringer was being manufactured at the time.
The 1856 Revolver was one of the first confirmed weapons in the game, first seen in the Jacob Frye Trailer. It is modeled after a Beumont Adams Revolver.
The Single Action Army is available in the game. The barrel of the in-game gun appears a bit longer than a standard Single Action army. The game is set in 1868, making the SAA anachronistic.
The Smith & Wesson 4th Model makes an anachronistic appearance as the ".38 Double Action". Although it incorrectly shoots .38 bullets rather than .32's, it is correctly identified as a double action.
The Colt Lightning is another weapon available to unlock in the game. It comes in two variants, the standard "Lightning" model, and the "Thunderer", which has better speed, damage, and quickfire accuracy.
The Self-Loading pistol is an anachronistic version of the Bergmann Model 1896. One of the better usable guns in the game, it has significantly higher stats than many other pistols.
The Mars Automatic Pistol is the final gun available in the games, excluding DLC. It is the most powerful gun in the base game, and has the highest stats of all firearms in the vanilla version. The Mars is ornately decorated and quite anachronistic, since it wasn't produced until 1897. An extremely rare pistol with a long-recoil and a production run of around eighty, the Mars was largely a failure due to firing a special round with a muzzle velocity more suited to a rifle; it was said that those who fired it never expressed any desire to do so again.
In the Steampunk DLC pack from November 2015, players were given new outfits, a new gauntlet, a new knuckle duster, and a new steampunk firearm called "The Rend Asunder". It is mocked up with a heat shield, long-range scope, and the various gears, whistles, and metal bits that are common in the steampunk art style. Although highly stylistic in design, the Rend Asunder appears to draw similarities with a Volcanic Repeater and a LeMat Revolver.
In a carriage chase from a cinematic trailer, a gangster trades his Colt Lightning for a lever-action rifle, which is most likely a variant of the Winchester Model 1866 "Yellow Boy"
In one of the game's promotional trailers, we get a quick glimpse of a royal guard with a rifle. Although we don't see exactly what is is, we it is most likely a Snider-Enfield Rifle, since that was the standard issue rifle of the British Armed Forces at the time.
The new variation of the Assassin Gauntlet has both a dart gun on top and a grapple launcher on the bottom. Syndicate is the first Assassin's Creed game to feature a grapple gun to make traversing rooftops easier and quicker.
