Anyone ever seen this before? A few of these showed up recently. Smaller than an M67, larger than a V40. Found in the US. You can see the stamped fragmentation pattern through the bottom, much like on an M67. 63mm long, 51mm in diameter at the seam. Filled with ballistic wax. Unusual that it is threaded on the outside of the fuze well, makes me want to think submunition or rifle grenade, but nothing comes to mind. I got an interesting unknown test drop submunition with it. Anyone got any ideas?