I have a can of hollow points and a can of FMJ. Both cans have headstamps that are very different, some say +p, some regular 9mm, some have the cross inside a circle. My first thought was the same as yours, that they were reloads with used cases. I know absolutely nothing about reloads. All of the projectiles match, that is, all the hollow points look the same and all the FMJ look the same. The stickers on the ammo cans does not indicate +p or not. For example , the FMJ says "9mm 115 Grain FmJ metal case, Factory loaded. I want to believe that they are all "regular" 9mm. My brother in law that owned them was a vet and knew a lot about guns. I dont think he would have mixed them all together.