"A custom part for the GM 79 that greatly reduces kickbak and gives each shot more stable trajectory."
The Shoulder Stock (GM 79) is a custom part in the Resident Evil 2 remake.
It upgrades the GM 79 by reducing its recoil and makes each projectile travel in a more stable trajectory, which in turn changes its aiming reticule. Needs to be combined with the weapon after being picked up. Upgraded GM 79 occupies 2 inventory slots instead of the base 1.
Inside a locker in the Elevator Controls Room, requires the Key (Diamond) in order to unlock the room.