Bahahaha, that's amazing.
What you need to understand about the model is that, even though the details are beveled in a way that makes it fit into the game, if you actually put the model in the hand of a player and look at it the difference in how many polygons are in each, the discrepancy becomes astoundingly clear. Further compare that to other weapons and it makes an otherwise really good model stick out like a sore thumb.
It does need to be dumbed down a bit. Not to the point of the regular gun, but enough that it can't really be picked out from a group of other people's stuff. Even though Bushido's add-ons are pretty terrible, he does a great job at balancing detail and simplicity in his weapons. I'd start there as a reference.
Quite frankly I prefer it when the details on the weapon outdo the player.
But that model looks like it has 20k+ polygons in it. I like how it looks, but it would probably lag like a bitch if everyone in a 10-player minigame was using it at the same time.
