Make at least one kill with every ranged weapon.

You must simply kill an enemy with each of the firearm weapons available to Artyom.

Shambler - Shotgun. You start with one in the very first level.

Kalash - Assault Rifle. You are given one during the Moscow level. Can be picked up off most human enemies throughout the game.

Revolver - Revolver. You are given one during the Moscow level by Yermak.

Bastard - Sub-Machine Gun. This can be picked up off most human enemies throughout the game. One can be found in a house on the water in front of you when you first commandeer the boat to at the beginning of the Volga level.

Ashot - Shotgun. Can be picked up off most human enemies throughout the game.

Tikhar - Air Rifle. Given to you by Tokarev during the Volga level.

Valve - Sniper Rifle. Can be found during the Caspian level from some enemies. Guaranteed drop from a sniper enemy on a crane that Anna gives you a mission to eliminate.

Bulldog - Assault Rifle. Can be found during the Caspian level dropped from certain enemies when helping Giul in the lighthouse.

Helsing - Crossbow. Picked up at the beginning of the Taiga level from a statue in front of where you start.

Gatling - Gatling Gun. Rare gun, dropped from the heavily armored enemies. One during the Yamantau level just before rescuing Anna, two during the Caspian level, one when you're attacked at the Aurora by the Barons men, the other when defending against the attackers at the top of the oil rig.