The animations aren't bad, and the model choice is good, but the rest could use some serious TLC. The normal map has absolutely no details to it whatsoever, which makes the model appear very bland where it should actually have at least some bits of detail applied to it.
Just as well, the diffuse has basically no details for a majority of the weapon outside of the few different shades of gray that are used; you could easily expand upon this by putting some labeling or markings across different sections of the texture, as what you have now is about as appealing as a rock.
Your specular also seems to be an exact clone of the diffuse, which basically serves no purpose at this moment in time since they are exactly the same; if you were just going to use the same file for the specular, you could have just had your .VMT point to the diffuse instead.
I can't really say much about the sounds. They're not overly impressive, but I can at least say that they are relatively fitting for this weapon. If anything, I'd replace the unsilenced firing sound and mag-in/mag-out sounds.
At the very least, I would adamantly advise going back and working on the diffuse for this, as well as working on the specular. I would also advise replacing your current normal map, as there is literally no detail to it whatsoever.
Overall, I can give this about a 5.7/10 in its current state. The model was a nice choice (though I can't say I'm too big a fan of the iron-sights), the animations aren't too bad, and the sounds are relatively fitting (sans what was mentioned before), but the textures and the current normal map are a serious hinderance for this skin in its current state.
Since the submission was updated, I'll go ahead and add a bit more info regarding the changes to the submission.
The tweaks to the animations are a nice touch. They weren't bad before, but keeping focused on the minor details tends to help, and it certainly did in this case.
While including a proper normal map is a definite improvement to this, I do have to say that the diffuse itself seems to have been downgraded in return, as now the diffuse is just a solid gray all over. The previous diffuse map had some different shades of gray all throughout the texture (although not very appealing, you could at least identify some of the different segments for the weapon). When I mentioned adding some details to the diffuse, I meant adding things like markings (scratches, small engravings, letters for the fire select switch, etc.) and labeling (as I suggested previously). Instead, you basically swapped out the diffuse for something that's just one solid shade of gray all across the board, and essentially left it blank. You'll want to try doing a bit of work on the diffuse now, as what you included for the diffuse now is even less appealing than before. It's good that you included a proper normal map, but swapping out the diffuse for something that's essentially just a blank slate wasn't a good trade-off. I'm sure there are others who would be willing to offer you some assistance if you need it, but take some time to work on the diffuse and add more details to it; It will help to improve this submission further.
The updated silencer-off sound is also an improvement over what you had before. I'd still suggest replacing the unsilenced firing sound and mag-in/mag-out sounds, however.
With the update to the submission applied, I can bump up my score a bit, but there's still work to be done before I'm willing to give it a higher score. Keep at it with the improvements, and I'm sure you'll be satisfied with the final outcome as well. And if necessary, take your time; you don't need to rush yourself in order to push out an update. I'm sure most of us aren't going anywhere, so take your time to work on the next update before you push it out; you'll be happier with the end result if you do.