Sweet M4A1! - your texturing style is very destinctive, I'm actually in the process of texturing a M4A1 for a DBPro project, damn fiddly things to UV map huh!.
I would hunt around for another weapons setup file, then copy it and change the objects etc, like hack your own weapon into it. I'm not sure of the best way to import your own stuff, I just hacked it like I'm suggesting to you. I'm sure there was a sniper snippet too, somewhere - you should look for that as it'd be a real shame if that sight did'nt work. You may need to animate it though to get it jerking when you fire, as well as the usual reload animations.
Van-B
Put away, those fiery biscuits!