I count myself as incredibly fortunate to have not been born in a time or place where I would end up on the receiving end of one of those shells.
My M-16 was self cleaning.
I had to clean it my self...................
Anzio
It sucked. We got them in early '67 and they started seizing up right away. They would tear the head of cartridge case off during extraction and then stuff a fresh cartridge into that. Crazy tough to clear and fatal if it happened in an intense firefight, which it often, often did. The Marines soon carried assembled cleaning rods, stuffed in a hole in the plastic forend so it could be cleared from the muzzle, like some throwback to the Civil War Springfield.
The sights were stupid - completely nonadjustable while you were using the rifle - and our Marines missed a lot because the rifles were hard to zero and windage was something you adjusted once while you were in the rear, maybe.
The safeties used to stick on Safe, the finish wore off almost as soon as you got them, the stocks were short and fragile and the rounds were often ineffective on the enemy; you could see the dust pop off them when you hit them squarely and they just kept running.
The enemy stuff never jammed - they did their R&D better than we did, apparently.
“Each of the nine 16-in. barrels on the Iowa-class battleships could be aimed and fired independently, sending a 2,700-lb. armor piercing shell ... pierce 20 inches of armor and 21 feet of hardened concrete. A 1,700-lb. explosive round leaves a 20-ft. deep by 50-ft. wide crater...”
This gets the capabilities mixed together, and details wrong.
The 16 inch/50 cal Mk 7 guns that armed the Iowa class battleships fired two shell types:
1. 2700-pound armor piercing (AP), Mk 8
2. 1900-pound high capacity (HC), Mk 13
AP shells contained a bursting charge of 1.5 percent of the total weight (no 40-ft craters). Armor penetration varied, depending on terminal velocity and angle of impact. Max muzzle velocity was 2500 ft/sec. Reduced-velocity propelling charges were also available: less bore erosion, lower dispersion at reduced ranges.
HC shells, intended for use against shore targets, contained a bursting charge of 8.1 percent of total weight. Max muzzle velocity was 2690 ft/sec.
Some years later, additional HC variants were put into service: variable-time (proximity) fuze, several types of submunition carrier, nuclear.
(pages 73-74, _Iowa Class Battleships_ by Robert Sumrall. Annapolis, MD: Naval Institute Press, 1988. LCN 88-71712; ISBN 0-87021-298-2)