Blank Firing Attachment
BFA - Blank Firing Attachment. Big yellow metal blob attached to the end of your weapon to enable it to use blank ammunition. I think it has something to do with stopping some of the gas escaping from the muzzle in order to re-cock the rifle via the gas mechanism as there is obviously no round fired to cause this as with live rounds. Please correct if wrong!
Due to most of the gas being trapped within the barrel and working parts of the weapon, it tends to get absolutely goppin' real fast. An absolute pain in the arrse after you've just been the fire support section for the Platoon-level attack, fired off loads of rounds and got back to the harbour, only to find the working parts have more carbon on them than burnt toast. Then you have to spend most of your admin time scraping all the crap off when you could be catching some zeds in your gonk bag. Happy days.
IMPORTANT NOTE: Should be removed if switching to live rounds otherwise something unpleasant will happen.