Mk46 / M249 (BFD)
The BFD prevents the loading of a Live M27 Belt into or be fired out of the Mk46 or M249. It only allows blank link to be fired. Due to the design of the BFD it prevents live link to be top loaded and will not allow the feedtray cover to close.
If a live round was linked into the blank link, the live round will break off prior to entering the feedtray.
This Safety feature assists in the proper function of the weapon system, with the ease of mind that live rounds cannot be loaded via link into the feedtray.
*This will not prevent live rounds inserted into a M4 magazine via the magazine well on the M249.
** Proper Physical inspection of Blank and Live rounds prior to any blank fire should be conducted by the RSO or unit level supervisor and operator of the weapon system.