What causes a failure to feed in a semiautomatic rifle/carbine?

A failure to feed in a semiautomatic rifle or carbine primarily occurs when the magazine is empty, as there are no rounds available for the firearm to load into the chamber. In semiautomatic firearms, the feeding process relies on the magazine providing a round into the chamber for the gun to function properly. When the magazine is depleted, there is nothing for the action to feed, which directly results in a failure to feed.

Other factors, while they can contribute to issues with the firearm, are not direct causes of a failure to feed. For instance, the release of the safety is part of the operation sequence but does not affect the feeding mechanism. Inexperience of the shooter may impact overall handling and operation, but it doesn’t inherently prevent the firearm from feeding if conditions are otherwise normal. Ammunition being wet could potentially lead to issues with ignition or extraction, but it is not a cause of the feeding process itself being interrupted directly.