Yeah, lots of ds's Y7 friend have it as well. One of his friends had the other CoD that is an 18 certificate when he was in Y5. That child had GTA as well.
So what? Ds knows he's not playing it in my house, and that's the end of it. When he gets his own flat and pays his own rent, then he can watch/play what he wants. Obviously I can't prevent him from playing it at friends' houses, but he knows why I don't approve. Once something's inside your head, you can't get it back out again. I really don't think young teen or preteen boys need to see that level of realistic violence.
I'm much more relaxed about videos, cos I can watch them myself and see why the rating was given (The Magdalene Sisters is an 18, for eg, as is This is Spinal Tap. Most of the Monty Pythons are 15). But computer games are much more opaque than that, cos so much stuff is hidden in the different levels. I don't like the graphic violence, and I don't like the way they engage the player on a first person level, making them the agent. If he wants to shoot things that much he can join the CCF in Y9 and learn how to shoot properly, y'know, in real life.