Update From my other m4a1, who was with some faces more.
Is not yet perfect, for tips on how to improve my models comment.
It's a great model but, you applied the modifiers to the model so I can't tell what level of subsurf you used. I understand that for use in a game that all the modifiers have to be applied so I get it. Just curious though, what was the subsurf level, more then 2 or 4 and was your goal in creating it for the purposes of game use? The reason that I ask is that you may not need a subsurf that high to achieve the same result. There are other modelling tricks too that may be more useful and that would cut down on the number of verts. To be honest I don't do game engine stuff so I am not as concerned with vert counts and some of my models reflect that "I don't really care bout vertices" attitude. I do have to say though that this is a great model. Textured and rendered it would be stellar even with the high vert count.