Early pre-WW1 U.S. Navy 4" projectile?


An interesting find at the site of the 1926 Lake Denmark explosion at Picatinny Arsenal was this 4"(?) U.S. Navy projectile having coarse threads for a very large base plug that I estimate to have been close to 3" diameter. The fact that the EOD Center at Picatinny had glass beaded it at the time when it was found tends to indicates that it was unusual find.