Yeah, this could be in Fallout 3 GD but I post it here simply because of more activity here.
Now, I was watching videos in Youtube and I ended up watching weapons vids. One of the weapons was http://www.youtube.com/watch?v=m7EfR4K17G8 anti-tank rifle.
Looking the video you must notice a great deal of similarities between L-39 and the Gauss Rifle of Fallout 3/NV.
+ Similar magazine (although on the side in the Gauss)
+ Almost identical stock.
+ Similar coloring
+ That lever-thingy used in reloading.
+ Almost idential triggers

http://www.youtube.com/watch?v=Z8DehAUimRA

And images:
http://images.wikia.com/fallout/images/4/4d/FO3_Gauss_rifle.png
http://cdn5.thefirearmsblog.com/blog/wp-content/uploads/2011/09/lahti-tfb.jpg

As pointless as this might be I thought it was curious, not only because of me sharing homeland with the gun but because of its rather unique features. Can't say I'm an expert on firearms but I've never seen another gun like that.

Could be, the origin of Bethesda's version of a Gauss Rifle.

M72 Gauss Rifle is still the best one.

It does look very similar from a design standpoint, but I have to say when that thing fired my face changed from this :mellow: to this :drool: