Wrong threads and too short - Streamlight Tailcap Assemblies for PolyTac Series Flashlights

I have two of the replacement caps. Neither will work on any of my Streamlight Polytac flashlights with replaceable non rechargeable batteries. Both are too short and the threads seem different. I could get one to work briefly by cross threading but the connection was so fragile that just moving the flashlight in my hand would cause the light to go out. For my use these are worthless. Maybe there are other models I don't have, I have three, but these were a total waste of money. Streamlight will be no help in finding a solution. This is the second model of that flashlight that has had the tailcap fail. A good tailcap from another flashlight works fine. Only the tailcap is bad but without a replacement the light is worthless.