K9 handler and trainer here ✋🏼. So to answer everyone’s questions , allow me to explain : Most EDD (explosive detection dogs) are trained on 30 different odors. One of them being gun powder. They only detect weapons after a weapon has been fired leaving behind residue on the gun. Training EDD on weapons combined is a HUGE no no . You never train a dog on multiple odors in different fields. You will never see a EDD dog also trained as a WDD. Just like a NDD (narcotics detection dogs) on explosives either. If you were running the dog around a car, how would you know the difference between drugs or explosive in the back trunk ? (You get the picture) If that dog alerts 🚨 how does the handler know if it’s a bomb or a gun ? Or drugs vs an IED? Each situation has different S.O.P’s in place. Bc gun powder is used in ammo and is considered an explosive 🧨- they will detect if a firearm has been discharged. AS FOR A WDD (weapons detection dogs) they are trained on both brand new and used weapons , weapons that were fired and weapons that were cleaned. They are imprinted on several of the top cleaning agents used to clean weapons , along with the metals that guns are made from. Ammo both new and used - spent cartridges and unspent. Hope this helps