Which of the following parts, if damaged, will cause a failure to feed? Choose all that apply.

A failure to feed in a firearm typically indicates that there is an issue with the mechanisms responsible for loading ammunition into the chamber. The magazine plays a crucial role in this process as it holds the cartridges in place and ensures that they are correctly presented to the chamber for loading. If the magazine is damaged, it may not properly hold rounds or may fail to push them up into the feed position, leading to a failure to feed.

Additionally, while the other components mentioned may have operational significance, they do not directly influence the feeding process as the magazine does. For example, the elevator is part of the magazine in some firearms and assists in raising the cartridges, but if the magazine itself is compromised, that will typically be a more immediate contributor to failure to feed. The trigger's function is related to discharging the firearm and does not impact feeding directly. Lastly, although the chamber must be clear and functional for the firearm to fire, a damaged chamber would usually lead to failures in firing rather than a failure to feed specifically.