Thanks a lot, Eghad!
Now that I've finished mopping up the drool on my desk...
Heist
The shotgun is a "close combat" weapon, meaning that it's best effective range is inside 200m. For combat teams in Iraq, you'd have one or two operators who would be part of your entry team. Likewise, at urban distances the shotgun is a formidable weapon because it can throw out lead in a huge volume of space, improving the odds of a hit.
Also, keep in mind that many of our enemies over there are prepared to die for their cause. What they aren't as well prepared for (so I hear) is surviving the encounter and being captured as wounded.