Some people like to collect accessories to accompany their collection, and the real thing is often not available, or even legal.
3D Printing has come a long way, and there is now a proliferation of people producing just about anything for just about any hobby.
This seller on E-Bay (
https://www.ebay.com/usr/makersteve) has been producing a series of 3D plastic projectiles that are inert display items (cannot be fired, no moving parts) that are ideal for displays or to complete your collection.
I would believe these to be treated legally in a different way to real projectiles, but replicas can sometimes fall under the same legislation, so best to check your
own countries' laws regarding importing and possession
before you order.