Notice the GIANT space between the butt of his carbine and his shoulder. At this point the shooter has as much stability as you would shooting an over-sized pistol, probably even less due to the length and weight of the rifle, especially with how close his vertical grip is to the receiver.
One of the most common pieces of advice I give shooters is to "get as much meat on the gun as you can." I don't remember where I first heard it, but it is one of the most solid pieces of advice I've ever been given. A good solid cheek weld, buttstock firmly in place against your shoulder. And it's an AR/M16 type of weapon, don't be afraid to get your face close to it, it's not going to kick you in the nose.
|Damn I look good!|
Good solid hold, what recoil there is on this gun is going straight into my shoulder. Solid cheek weld, which enables you to maintain a consistent sight picture.
Another picky point about the first shooter. Notice how high up the rifle is in relation to his shoulder. Here's a classic MS paint visual aid-
The red line is going straight through the boreline of the rifle. Notice how Mr. Stoner conveniently placed the stock on that same line. Pretty smart guy.
Unfortunately, the soldier in the picture has the rifle high up in his shoulder. Notice the arrow sailing straight over and past it. If the carbine was in contact with his shoulder, it would just be the toe end, and combined with the high force vector, this causes the toe of the stock to act as a pivot point, causing an increased amount of muzzle climb.
Scroll back up to the pic of me, and notice the empty case hanging just past my shoulder, and note the photo is at the moment of firing. Quick controlled pairs on that rifle are lots of fun. Full contact of the butt transfers the force evenly against the shoulder, and preventing that pesky rotation, which is the reason that the stock is in line with the action in the first place. Having full contact with the buttstock on an AR/M16 type weapon reduces the muzzle flip to nearly zero.
Just had to get that out of the system.