Hubert, most halls of residence contracts state you're not allowed anything that resembles a weapon on the premises, some do not. If you're lucky, they won't, in which case you are completely okay to have it.
You are a paying tenant (or in this case, licensee), as such, you have and hold all the rights of someone who would rent any property or permanent accommodation, minus anything listed in your agreement with the "landlord". Provided it would not violate the contract of tenancy or license, and is within the confines of the common law (which storing an RIF or IF is), you may store your carbine on the premises.
My previous halls had a ban on "BB guns" and anything that resembled a weapon; as a result my AEG and shotgun weren't really allowed, I just made sure that they were kept in a lockable hardcase (something big enough to look like it could hold a guitar) and whenever I handled them, I locked my door to prevent unannounced entry. On one occasion a cleaning lady saw my AEG and wasn't remotely bothered.
Unless you run round waving it above your head shouting "dakka dakka mohammad jihad" whilst wearing a turban and shooting people with it, your "halls admin" team will probably have bigger fish to fry (for example, our halls team had to try and sniff out and catch someone who was dealing meth).
Hope I helped
