[Lurker]

I fail to see the utility of converting to a submachine gun caliber

The only reason I could see is if you wanted to use a supressor. If one wished to fire subsonic 9MM or .45 ACP rounds I suppose it might make some sense.

One of the private ranges I do 3 gun shoots at won't allow the use of 5.56 ammo, so quite often we use an AR with a 9MM upper for that event.

Those are about the only reasons I can think of.

L

[Travis McGee]

Good point.

[Erik Latranyi]

The only reason I could see is if you wanted to use a supressor.

Close Quarters Combat, something our military is involved with in Iraq. When indoors, shooting a rifle cartridge that penetrates walls can result in friendly fire accidents.

Also, the stopping power of the .45ACP is proven in Iraq.

You keep the rifle cartridge for battlefield conditions where combat takes place at ranges greater than 50 yards.