Nigeria, one of the reasons is, there have been illegal possession of local made and unregistered guns and this has led to many communal fictions and killings.

Recently, we had an outbreak of people killing masses of people in the name of redemption.

Things like that made it a no-no. However if you are influencial enough (which I am not), you can hold it without any restrictions.

In cases of "snitch" which is very ramphant, a gun holder may be termed "bandit" or at worst "terrorist" and be severely punished

Try googling "boko haram"