Funny. I was scuba diving for lobster in an out of the way place between Portobello and Isla Mamey. “The Sisters” IIRC. 1992 approx.
I found a 2 inch PVC pipe about 6 inches long sealed at both ends with end caps glued in place. Intensely curious when I got home it was with some trepidation I broke it open. I made the kids go inside. It had been packed with grease and a .223 round and a .45 round. IIRC for some reason I felt it had been in the water a year or two from a date inside or something.
The grease had deteriorated badly and the ammo was so corroded I am certain it was useless. I still wonder who did that. Was it one of yours?
Might of been from the TTC. The test had been done a few years before, but It seems possible that a test item got washed down to a river and out to sea. 200 inches of rain per year on that side of Panama.