Someone was using their heads on this one. A projectile body modified to hold four fuzes on plates inside the projectile body. Setscrews hold the plates in place so they will not come loose. A way to test operation and functioning of up to four fuzes at once by recovering the projectile and removing the undamaged fuzes. They would receive the same setback, rotation and deceleration that they would installed on the projectile in a normal manner. This one happens to be a 155mm, but it would work on any caliber. Never saw or heard of such a projectile on the test rangs I was around.