What's the Name of That Book??? discussion

Protagonist and other teens are sent to a camp for teens. They think it's temporary, but it's actually a camp where parents send troubled kids to be murdered. One of them is able to call home, but the parent freaks and thinks it's a prank since they should be dead. I read this in the mid 2000s

The Grounding of Group 6

I also think there was a bullet on the cover.

YES THANK YOU!!!!

You’re very welcome!
That’s a popular book here. Five others have searched for it, which is how I discovered it.