Excessive headspace in a blowback firearm can cause which of the following?

Excessive headspace in a blowback firearm can lead to firing problems due to the way it affects the chamber and cartridge alignment. In a blowback operation, the cartridge case must fit snugly in the chamber to ensure that it is properly supported during firing. If there is too much headspace, the cartridge may not be secured correctly, which can lead to misfires or failures to fire entirely because the firing pin may not strike the primer effectively.

Additionally, excessive headspace can cause the cartridge case to stretch or yield during the firing process, leading to failures of the case to extract or eject properly. This instability during the firing sequence may also result in inconsistent ignition, contributing further to firing problems.

While excessive headspace could potentially affect other areas like recoil or ejection, the primary and most critical issue it introduces is related to the reliability of the firing mechanism itself. As a result, identifying and correcting excessive headspace is vital for the safe and reliable operation of blowback firearms.