Mounting the Rifle/Carbine

      What is the best way to mount a rifle to your shoulder? It seems to differ according to age (generation), type of rifle, and type of shooting.

       Shooters using older rifle designs with a traditional rifle stock (e.g., the M-1 Garand, the M1903, or a standard bolt-action hunting rifle) generally will hold the rifle in a refused stance (the dominant foot placed well behind the off-hand foot), which provides the minimal target area to a potential enemy to the front while providing better footing to avoid being pushed back by the recoil.

       In such a stance, in order to bring the sight up to the eyes (rather than cant the head along the stock), the shooting arm (generally the right arm) is brought up high with the elbow projecting outward and about the same height as one ear, but at least level with the shoulder. (Ignorant shooters ridicule this as the "chicken wing"). This provides a firm grip on the stock of the weapon, aligns the shooting arm with the shooting hand, and brings the shoulder pocket up high enough so you don't have to lower or tilt your head. This is important with a rifle that has medium to high recoil, such as would have been used prior to the adoption of intermediate cartridges such as the 7.62x39 or small caliber rounds such as the 5.56 NATO.

      An example of this can be seen in this World War 2 training movie (at about the 20 minute mark) on rifle marksmanship using the M-1 Garand Rifle.

"Rifle Marksmanship with the M1 Rifle - Preparatory Training"--Mindwerkz 

      Notwithstanding, most people who shoot medium to high recoil rifles with standard rifle stocks will still hold a rifle with the elbow raised. This still creates a pocket to control recoil and keep the rifle high enough that only a slight canting of the head is necessary to use the sights. (See photograph below).

John Garand demonstrating his rifle (Source) 

However, you can see that even with the elbow dipped that low, the alignment of the arm to the shooting hand is somewhat compromised.

       There is a time when using a traditional stocked bolt action rifle when you will have to lower the arm closer to the side, and that is during rapid fire. Operating the bolt with your fore-finger and thumb, while using your middle-finger to operate the trigger, pretty much requires a lower elbow for the best results.

      Weapons with a pistol grip (such as AR 15) are best held with the shooting arm brought close in to the side of the body. (See the Vietnam era training video below). This aligns the arm better with the shooting hand.

"How M16 Rifle Works | XM16E1 | US Army Training Film | 1966"

The Best Film Archives (20 min.)

The main reason this is practicable is the light recoil impulse which allows the weapon to be mounted to the shoulder without the need to create a deep shoulder pocket.

Source: "The Right Way to Shoot an AR-15"--Shooting Illustrated

         As the author of the Shooting Illustrated article, above, notes as to the AR-15, "[t]he toe of the buttstock should be placed high and tight, inside—not on—your shoulder. If placed on the shoulder it can work its way out during repetitive firing. If placed too low, you'll have to lower your head to see the sights. ... When mounting an AR, bring the sights up to your eyes. Don't lower your eyes to the sights." He also observes:

The pistol grip of the AR should be held firmly and used to pull the rifle into your shoulder. Also, pull the rifle back with the support hand. This is easiest with a vertical fore grip, but can also be accomplished by using the magazine/magazine well, and to a lesser degree, via the common handguard hold.How tightly should the AR be held and how firmly should it be pulled back into the body? Point the AR down range, looking through the sights at a target. Increase your grip tension and reward force until the AR begins to wobble. Then, reduce pressure until the sights stabilize. Hold it firm and tight—but not too firm or too tight. Because the AR is often employed as a rapid-fire weapon system, your hold needs to be a bit more rigid than it would typically be with a bolt-action rifle.

He continues, speaking of shooting off-hand while standing:

       Standing, off-hand is the least-stable field position. It's also the fastest to assume and it's imperative to master because it allows the most mobility and can be obtained quickly from a dead run. Ideally, feet should be about shoulder-width apart with the off-side leg/foot slightly forward. Legs should be bent a little and your shoulders vertically aligned with your toes and knees. This makes for a slightly weight-forward posture that helps with recoil. It's a fighting stance, much like you assume when shooting a pistol. 

       From a tactical perspective, it's important to tuck your elbows in tight to the body. This keeps you compact and makes it easier to negotiate hallways and doorways and not elbow a team member in the nose. It also keeps elbows from giving you away when slicing the pie around corners and permits better control of the AR when engaging targets with fast-paced, multiple shots.Some shooters like to position their weak hand on the handguard, close in front of the magazine, using the magazine/magazine well as a vertical fore-grip. 

The author recommends a vertical fore-grip, but there are several fore-grips that are designed to be used with a C-clamp style or hooking just a couple fingers around it which I believe are better. (See, e.g., the video below).

      There are some objections with a "fighting stance" style of shooting a rifle, which Herschel Smith, of The Captain's Journal, brings up (criticizing the stance pictured in aforementioned Shooting Illustrated article). Instead, it is recommended that the shooter stand square, almost in a horse-stance.  (See the video below).

"How to Shoot an AR-15 / M4 Carbine"--John Lovell (11 min).

Herschel Smith refers to this as a forward-aggressive stance. The primary advantages claimed for this stance is greater view over the non-shooting shoulder (i.e., you can turn your head further to the left) and that it presents your chest plate directly toward an enemy, instead of exposing gaps in your armor. 

       Obviously, if you aren't wearing armor, the second point is inapplicable and, in fact, you might want to turn to minimize your target size as taught back in World War 2 and Vietnam (and one of the reasons why fencers turn their bodies). The first point is also only applicable to urban combat or CQB. So good for using an AR inside your home or in a competition, but not necessarily as good when shooting in the field. I would also be concerned with recoil knocking one off balance when shooting a more powerful round, such as the .308/7/62 NATO. 

       Anyway, like the answer to most questions in life, the answer to the question I raised at the beginning of this post is: "it depend." What is appropriate or best for one type of rifle may be inappropriate or incorrect for a different rifle.