>I think, standard practice is no personal arms at all when in areas
>with prisoners. The idea is that arms can be taken away and used
>against the guards.
An Justice Department investigator was killed inside a federal prison a couple years ago when agents came to arrest a guard and the guard started shooting with a personal weapon. Agents hadn't expected the guard to be armed for the reason Chuck gives here.
If prisoners are outside walls, like on a work detail, guards have weapons. A couple of prisoners on a work detail in Texas last fall escaped for a few hours after taking guns from guards and killing one guard.
Standard policy also includes "non-lethal" weaponry, like rubber bullets and tasers. One prisoner died after being shot in the head with a rubber bullet fired by a guard from a tower. The guy was in a coma and shackled to a hospital bed for a few weeks before he died.
http://www.cbsnews.com/stories/2006/06/21/national/main1736630.shtml
http://www.signonsandiego.com/uniontrib/20050310/news_1n10inmate.html