Which malfunction may be caused by a damaged lug on the bolt?

The malfunction that may be caused by a damaged lug on the bolt is a failure to chamber a round or failure to extract. The lugs on the bolt play a critical role in locking the bolt in place within the chamber and ensuring that the firearm operates correctly when cycling rounds. If the lugs are damaged, they may not engage properly with the corresponding locking surfaces in the barrel extension, which can hinder the bolt's ability to fully chamber a round.

When a round is not properly chambered due to this misalignment or insufficient locking, it can lead to a failure to chamber the round, as the bolt is unable to completely push the round into the chamber. Similarly, if the bolt does not lock up correctly, it can also affect the extraction process after firing, leading to a failure to extract the spent casing. This malfunction can manifest in various ways, such as the firearm failing to fire due to a failure to chamber or having difficulty cycling spent cartridges out if extraction is compromised. Understanding the role of the bolt lugs emphasizes the importance of ensuring they remain in good condition for proper firearm operation.