American troops in Iraq are discovering, through combat experience, that more changes are needed in the type of weapons they should carry. As the U.S. Army Special Forces have discovered, if you are well trained and know what you are doing, you should carry a pistol, in addition to your rifle. But not the official issue 9mm pistol, but something with a bit more stopping power. The Special Forces prefer a new model .45 caliber (11.43mm) pistol, although 10mm weapons are also popular. The reason for this is that you are most likely to be using the pistol indoors, where your target is going to be really close. You want to knock him down quickly, before he can get at you with a knife, or even his hands. Many troops are getting their own pistols, and most commanders have been lenient on this issue. The same applies to shotguns. Although the army and marines have bought a lot of them (the Benelli M4 Combat Shotgun is a particular favorite), there never seem to be enough of them for some units (that spend a lot of time raiding buildings in hostile neighborhoods.)
Some troops also buy high tech electronic sights, when the army or marines has not gotten enough good stuff to equip everyone. Combat troops have also found it useful to learn how to use the AK-47, whose larger bullet has more punch at close range, and is more useful when firing through ceilings and interior walls. Some units collect captured AK-47s, select the ones in the best shape, clean them up and keep them handy for some types of operations. But just knowing the basics of operating an AK-47 is useful knowledge, which you'll never know when you'll need.
The troops also appreciated the getting the most realistic urban combat training possible. This included the use of modified (to fire slower bullets that sting, but don't break the skin) pistols and rifles in "kill houses." Here, training can be carried out with live ammo. Kill houses are also equipped with vidcams, and the troops particularly like to watch the vids of their performances. Seeing your mistakes apparently makes it easier to correct them.
All of this stuff is old news to the Special Forces, which have been doing all of this for years. But the army and marine grunts are smarter, better trained and better led than at any time in the past. That's always been the description of the Special Forces, so it's not surprising that the better quality "regular infantry" are starting to adopt Special Forces techniques.