In addition to its role in cycling the action of a weapon, the BFA also prevents debris from the blank round (and in some cases, inadvertently loaded live rounds) escaping. This debris could cause injury to nearby personnel if the BFA has not been fitted or has fallen off.
The BFA performs another task besides facilitating weapon operation by keeping debris from blank cartridges and, in certain instances, inadvertently loaded live rounds contained. If the BFA is missing or detached, this debris might harm individuals close by.