Cardan's Saiga-12k

A shotgun that can be made after handing in the blueprints to Vasily along with two Gravi, one Ruby Spring, a Saiga-12k "Sniper", and a Saiga-12k "Tactic". It comes with a built-in collimator sight and a 12 round magazine, as well as a full-auto firing mode.
==Location==
* Crafted by Vasily after completing Tools for Vasily.
You'll also need the blueprints, which are the final reward for Screw's chain quest. The chain involves giving him an entire series of weapons upgraded at Lanky.
Each upgrade takes one full ingame day to complete, so if you want to obtain this weapon, it's better to start collecting and upgrading the required items early on; however many of the weapons can be acquired in their fully upgraded form, saving time. Look at the list in the link above for the full list.
==Notes==