5"/38cal Clearing Charge.
The clearing charge (also called, "the short round") is a short case; plugged just above the wad.[19] The distance piece between the wad and plug is left out. Its powder charge is less than a full service charge.[19] This case is essential for the safety of the mount because it is needed to clear a gun after a misfire.[19] Due to its importance, it is kept in a special container in the mount whenever the ship is in a combat zone. A misfire is especially dangerous in semi-fixed guns.[11] When the breech is opened after the misfire, the faulty powder case can be extracted, but the projectile will remain jammed in the rifling.[19] Also, all or part of the extracted case's cork plug may still be wedged in the chamber behind the projectile. This "fouls" the chamber because it decreases the chamber's volume. And, since Full and Reduced charge cases take up the full volume of an unfouled chamber (see loaded Semi-Fixed round drawing above), any residue left from the previously extracted case will prevent them from fully loading into the chamber. Therefore, the clearing charge is made short so that it will fit into a fouled chamber.
After hand extracting the bad case from the chamber, the clearing charge is removed from its special container and is hand rammed into the chamber. With the clearing charge sealed in the chamber, the projectile is fired out the muzzle.[11] It is important to clear the projectile through the muzzle because it is not easy nor safe pushing a bore rod down the barrel to force a fuzed projectile back through the chamber and into the gun house.[26] Also, if the gun has fired a number of rounds just prior to the misfire, time is critical because the barrel may be hot enough to cook off the high explosive in the projectile.[27] This would destroy the mount.[11]

See also

Weapons of comparable role, performance and era

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