Q. I’m joining the army as a chaplain. Can I carry inside the building or inside the fenced army camp during Shabbos?

A. Horav Shlomo Miller’s Shlit’a opinion is that even if they are other Jewish soldiers stationed in the camp it is permitted, since the camp belongs to the army, an enrolled soldier is dwelling as a “guest” in their property and can therefore carry without an eiruv chatzeiros.
As far as the fenced outside camp, if the doors are more than five meters wide, but for security reasons are mostly kept closed, the door slides on a frame with an upper edge, it is a double door, or has a protective chain or bar, it is permitted. If in doubt whether the door is closed on not, it is also permitted.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a