I crawled into the attic, grabbed four books on shooting; no mil manuals, though I'm sure they're here somewhere.
All four prescribed 'elbow up', with only a little more-
Captain Paul Curtis, in Guns and Gunning, noted:
"The right elbow is held a little higher than the horizontal position. When this is permitted to sag, it tends to drag the rifle over or cant it to the right."
And Jack O'Connor, in Complete Book of Rifles and Shotguns, wrote:
"...your right elbow should be about level with your shoulder and the butt of your rifle against the pad of muscles formed at the shoulder joint. If the steel buttplate is farther inside against your collar bone, the recoil is apt to hurt, and if your right elbow is down toward the waist it is difficult to get your right eye in line with the sights with modern stocks."
Again, I tested. If I mount elbow up and then flap my wing, the gun very obviously rotates. And if I mount it elbow down, the pocket is not comfortably vertical and the rifle wants to sit at a right cant.
I didn't notice any difference in cheek placement or sight line, mounted down. (Sorry, Jack.)
Why on the why- A friend has demonstrated the need for some instruction, some thirty-five years into his shooting career, so I'll soon be out in the hills with him. Although I can give orders without comprehending their reasoning (I spent enough years in middle management!), I'd much rather be able to explain and justify what I say. I learned the position while too young to care, but anymore I want to understand what I'm doing and why; and I like to offer same to those under my tutelage. Plus, the reason will dictate how strongly I insist on performance.
So, this is classroom prep.
