Installing a muzzle brake allows recoil to be reduced significantly.
― In-game description
The Flash drive with data on a submachine gun muzzle break is a mission item in S.T.A.L.K.E.R.: Clear Sky.
General information[]
The flash drive contains upgrade data for a Viper 5 submachine gun and can be delivered to Gray in the Clear Sky base at the Great Swamps for a reward of 1125 RU, after which he will be able to apply the upgrade to the player's weapons.
Location[]
Location of the stash
The flash drive is located in a stash at the Great Swamps named Backpack on corpse. The location of the stash can be bought from Nimble for 100 - 900 RU. His offer is randomly generated, so decline and ask him again if his price is higher than one would like to pay.
