Gauss Rifle can be found in Pripyat
( How to get there I told in my guide right after the prologue )

When we got to Pripyat, we went to the "Prometheus" cinema.

There we find a side door, and throw a grenade under it with the right mouse button, as shown in the screenshot.

The grenade must pass under the door and blow up the boards on the other side of the door, causing it to open.

fter that, go inside and go straight and left.

Our Gauss Rifle will be there, you definitely won't miss it, as it will be illuminated by a desk lamp, the only one in this dark room.

After we have hooked the Gauss Rifle, we go to the "Druzhba" ( or "Friendship" I don't know what it's called in the English version of the game) kindergarten.

We approach the main entrance to the building and pay attention to the left window near it, that's where what we need is located.

We jump onto the part of the bed that sticks out of this window.

Let's go into this room, there will be a bag here with an enlarged store, and a nice bonus in the form of a Guard exoskeleton

We actually open the bag and loot the 20-round magazine from it.

Sorry for my English and any mistakes I made, it's not my native language.

Thank you for reading this guide, good hunting, stalkers!