2 Inch Rockets
Hi SG500 just to put things straight, the Rocket Aircraft 2 Inch (R/C 2 IN) was mainly used for aircraft with a wing mounted "Pod" housing about 20 of these rockets.
Like the SNEB system the rockets fins "spring" out on exiting the firing tube and drop back then lock in the extended position, whereas the SNEB 68mm Rocket fins actually push forward under gas pressure.
These aircraft Rockets were available in Practice, High Explosive, Armour Piercing, Cannister shot, also a White Phosphorus smoke round was made but I dont think it ever saw service.
The AP head that you have needs another adaptor to enable it to screw into the rocket motor tube, it may even be that the Armourer unscrewed the PRF 942 (Plug Rep Fuze) from a Practice round and replace with the AP nose as the threads are the same-or, you are missing an adaptor !
I only have two part pictures of the rockets but it will give you a good idea of what it is you seek.