It is a single-action revolver with a high capacity nine shot cylinder. This weapon's high capacity allows for more shots between reloads and allows the player to gain the upper hand, especially in short, intense firefights. In singleplayer, this weapon is capable of killing an enemy with one shot to the chest or head, and is capable of taking down some predatory animals with one shot as well, such as wolves as well as bears if aimed properly at the head.
The LeMat is the most powerful revolver and second most powerful handgun (after the High Power Pistol) in the game.
Right after reloading, the hammer is left in the uncocked position until the first shot is fired. After this, the hammer becomes cocked and will be cocked back for the remainder of the rounds in the cylinder or until the next reload. This odd occurrence affects all firearms with a visible hammer in single and multiplayer.
In reality, the LeMat featured a second 16-gauge smoothbore barrel beneath the main barrel that could fire a single charge of buckshot. While this second barrel is modeled visually on the weapon in Red Dead Redemption, it is unusable.
The original Civil War-era LeMat was a cap-and-ball revolver, making it extremely slow to reload; a few examples of a cartridge version were made in later years in Belgium, but none of these are known to have left Europe.
After the mission An Appointed Time, if the player gets into a shootout with the Mexican army, the Gunsmith in Escalera will run away and never return, leaving the LeMat unable to be purchased (It is possible to undo this glitch by camping in the wilderness for about five days. The gunsmiths and store merchants should return then).