And MP's classically are used with ballistic shields in raids!

Usually, a ballistic shield-man would carry a pistol, with a cover guy using a long gun.
Police tend to eschew machine pistols here, as Spray-n-Pray tends to lead to a LOT of paperwork. The red tape is bad enough if you shoot a bad guy, but when you start hitting innocent bystanders, nuns, kids, pets...
Man, do you have
any idea the amount of scrutiny they'd come under if they hit a
dog?!In the United States, anyway.
Maybe, in less civilized places, they're okay with stray rounds hitting stray dogs. But here, in America, you can only shoot your own dog.

Where was I? Right...shields.
While in reality, they tend to be used mostly by Law Enforcement, I think shields are one of the most overlooked pieces of gear - my Troll
Mage owns one, keeps it in the van for a bad day. I mean, he's a Troll, he doesn't carry a long gun, and once they figure out he's a Mage he's Gank Priority One...nice to have a solid wall to carry around for cover.
-Jn-
City of Brass Expatriate