The Rattlesnake is a Weapon in Rise of the Tomb Raider. This special Revolver is a golden variant of Nagant. It was available as a Community Reward to players who started playing the game before the deadline of 30 November 2015. It's overall performance is equal to the Nagant.
Unlike the Nagant this weapon is available as soon as Lara sits down at the first Base Camp in the Siberian Wilderness; it has not to be collected in the Soviet Installation like it's Nagant counterpart. This behaviour is due to the fact that it is a give-away for early adopters of the game and and behaves like a Downloadable Content. However, the Rattlesnake can not be used until the Nagant revolver has been found. This is in order to not give early adopter a unfair advantage.
The Rattlesnake features exactly the same upgrades as the stock Nagant revolver: Nagant#Upgrades.