It's the obsession with collecting weapons, especially if they're old.
Obsessive a hobby for weaponry. From Greek 959; 960; 955; 959; 957; (hoplon, "weapon") and 956; 945; 957; 953; 945; ( mania "madness", "obsession" ).
A term that can be related to OPLOTECA (collection of old weapons). By its components, it could be defined as a hobby or obsession with weapons.