Back at RAFC, before plastic webbing made its appearance, the only way to get a blancoe'd webbing 'sling' to fit one's 7.62mm shoulder cannon with the required tightness was to operate the locking lever to open the weapon, attach the ends of the sling to the swivel jobbers, then snap it shut. Naturally this didn't do the rifle much good as it put rather a strain on the locking thing...and was strictly forbidden.
One miserable early morning, a Flt Cdt duly attached his webbing in this outlawed manner. All went fine until the command 'Preeeeesent...ARMS'. On the second movement, which involved a smart smack to the side of the weapon, the locking thing decided it had known better days. The rifle bent in the middle (like a one string fiddle) and in the ensuing silence, just before the band struck up, the sound of various bits of oily black metal escaping from the rifle and rattling onto the parade ground could be heard, amongst much general tittering and guffawing. Needless to say, the parade commander went into low earth orbit; Flt Cdt Dimwit and as much of the remains of his SLR as he could find were promptly booted off the parade ground.....doubtless to be awarded many days 'Strikers' for such a co.ck-up on parade!