Which of the following is NOT a shotgun malfunction?

The selection of "Failure to scope" as the correct answer is based on recognizing that this term does not represent a recognized malfunction in shotguns. In firearms terminology, malfunctions typically pertain to issues that prevent the firearm from functioning as intended, such as failure to extract, failure to feed, or double feed.

Failure to extract occurs when the spent cartridge case does not get removed from the chamber, leaving it in place for subsequent shots. Failure to feed refers to a situation where a round does not properly enter the chamber from the magazine or feeding mechanism. A double feed arises when two ammunition rounds attempt to enter the chamber at once, which can cause a jam.

"Failure to scope," on the other hand, does not relate to a malfunction of the firearm itself; instead, it likely refers to an issue pertaining to the aiming mechanism or to the use of optics, which is a separate concern from the functioning of the shotgun. Thus, this choice stands out because it addresses a different aspect of firearm usage rather than a mechanical malfunction.