Reunion

Clear Sky. To the north of Marshlands - the starting location, near the trainwreck, you can find a VSS "Vintorez" rifle. It is fully broken and empty, but that can be fixed and Vintorez is considered one of the best weapons in the game. Sure, it has lower range, but even default 9x39 SP-5 rounds chew through body armor and it's precise enough. Can also be used as an assault rifle in a pinch, it can go full-auto. Definitely worth giving some cash to Novikov (Clear Sky mechanic) to fix it.
Why this screenshot is called "Reunion"? Well... it's implied that it's a player character's rifle, which he lost after he and three scientists he led were hit by a blowout. You can see this place in starting cinematics, and Scar the Mercenary is armed with a Vintorez. And there are also three corpses clad in SSP-99 suits (basic Scientists' outfit) laying nearby.