Those are a good start.
They look sort of 70's Sci-Fi
I think people might criticise the fact that you've built them out of primitives, but I think they'd look ok with a good texture.
----Critique----
Left gun:
I dont really like the trigger guard, the sphere looks like it might be covering up some messy poly work underneath (where the two rectangles of the guard meet). This is personal, but I'd like to see a wider box at the top of the magazine, where it enters the gun. Other than that it looks funky,although you might want to extend those round bits on the barrel, cuz when you view it from the side in FPSC, you might not be able to see the cool detail.
Right gun.
I like this gun, it looks like the supershotgun from quake..I think. My only two things to say are: The cylinder that you have used for the bottom of the gun will up the poly count unneccessarily. You'd be better off using a box, smoothed on the bottom. At the moment I'm guessing that half that cylinder dissapears inside the gun, and gets wasted. Other than that, just sort out the handle and you're there.
I dont want to sound like I'm having a go! I'm trying to, you know, give you some constructive feedback.
But you've made a nice start. Keep it up!
(im downloading now....btw)
___!!Edit!!____
I checked out the models and they're cool. I'm uploading a pic to help you cut down the poly count and make the guns look smoother.
peace
"It's often better to keep your mouth shut and let people think you're an idiot, than to open it and confirm their suspisions" - Noel Coward