I saw this pic, and my first thought was: why does the U.S. military use this silly “slope arms” position?
For those who’ve never had to march with a rifle, here’s my gripe: that trigger guard is going to keep digging into your collarbone, and after a while that is going to be owie.
Far easier, in my experience, to hold the rifle side-on, with the trigger guard on the “outside” (away from) the neck.
The grip on the rifle is more secure (the left wrist is horizontal rather than vertical, as above), similar to the way one would do curls with weights in the gym: the biceps work better that way, ask any lifter.
More importantly, the “sideways” slope arms accommodates a longer magazine because it lies on its side along the upper body instead of once again digging into the body.
I welcome comments from those who know more about U.S. military drill than I do.