Nicely done. I would like to add that firing from the hip is less accurate. depending of course on how much one practises it and the range involved. But generally, less accurate.
if you really wanted to put something else in there you could put something about the BAR actually being designed for "walking fire" with a hip issued holster but it has no pistol grip.
no military in the world teaches recruits to fire from the hip
I doubt it was ever used in combat, but it did exist.
I think the whole hip-fire thing comes from the way that two-point slings allow you to carry the rifle/shotgun on your person, at the ready, without bearing its full weight in your arms, if you sling it over your shoulder, and hold it waist high.