Nice concept for a hack but it could have been much better.
The textures look out of sync. While making a custom hack composed of multiple parts, you should try to normalize the color across the textures so that they look uniform all over the weapon.
In this case, the scope, the body, the buttstock all have very different shades of black and white that do not play well together.
The wooden grip seems much out of place. You could either make a matching buttstock as shown in the inspiration pic or make the grip metallic again.
This actually could have looked much better if you took textures Teh Snake's pack since you would not have to do much editing here as they all mostly follow the same dark palette.
You also seem to have selected a pre-1.6 version of the models where, the scope UV map is quite large and only 1/4th of it is being used. The meshes have also slipped from their original positions - this happens usually while compiling and their position has to be adjusted prior to compiling to make up for the offset (usually to the left by 1-2 units).
Finally for completeness, you could make PeeWees and sprites as well. Those are trivially easy to make, once you get to know the technique and usually don't take more than 10-15 minutes to create once you get accustomed to making them. Unless you already know how to, you can refer to making sprites and making PeeWees.