The Fundamentals of Shooting

The fundamentals of shooting are not a secret and neither are they rocket science. However, it is vitally important to get it right and practice, practice, practice.. In my opinion it is vital to get the fundamentals right before progressing to any ‘high speed’ combat style shooting.
The U.S. Army taught fundamentals of Marksmanship can be summarized as:
Steady Position
Breath Control
Trigger Squeeze

And to show that these are not a secret, you can read all about it HERE in detail.
IMO, correct shooting training should progress from the solid basics up through increasingly dynamic combat/tactical style training. If you don’t get the basics right, you will not have the solid foundation to build on for the more dynamic stuff.
On my Combat Rifle / Contact Drills course, I cover these basics on the first morning, as a ‘remind and revise’ before moving on. Its important to note that I expect those attending my course to already know how to shoot and handle their weapons at a basic level, such as square range or target shooting. My course is designed as a transition from such shooting to a combat environment.
In my training experience, spanning British Army Paratroopers through local nationals and contractors in places such as Iraq and Afghanistan, I have always looked back to British Army techniques, such as used in the Systems Approach to Training (SAT) used with British Army infantry recruits. Marksmanship training will follow a process based on the following:
Grouping & Zeroing: the basics of marksmanship, shot grouping etc.
Application of Fire: shooting out to various ranges to take account of range and wind effects, watching fall of shot, estimating range and adjusting sights/point of aim accordingly. Short exposures of the targets and multiple targets at various ranges.
Transition to Field Firing: Controlled ranges to introduce movement of the firer, movement of the target, reaction drills, exposure times for the target, multiple targets and engagement under combat conditions.
Field Firing: Tactical engagements under combat conditions, moving from individual up to unit formations. Battle drills, suppression, tactics, assault, break contact etc. 
What you get when you attend my Combat Rifle / Contact Drills course is a weekends training that takes you from your square range experience and moves you through transition to field firing on to field firing.
The British Army Marksmanship Principles are as follows:
1) The position and hold must be firm enough to support the weapon.

2) The weapon must point naturally at the target without any undue physical effort.

3) Sight alignment (i.e. aiming) must be correct.

4) The shot must be released and followed through without disturbance to the position.

Immediately you can see 1) the fundamental application of this all the way up from range shooting through field firing and reactive close range combat shooting 2) although some of these principles are harder to apply in a dynamic situation they will still be your basic foundation as you move on to dynamic combat environments etc.
OK, so lets take a look and summarize the application of these principles: 
1) The position and hold must be firm enough to support the weapon: this is about building that position using natural body physiology and without excessive strain. Depending on the position, you will always need some muscular effort to hold the rifle in position, but you need to minimize this and relax as much as possible. Muscular effort means strain and ultimately shaking and fatigue, all messing up your group.
Lets take the prone position as the starting point and the example. As you build up to other positions, such as kneeling or standing, the principles apply but you will find yourself with less support and more of a requirement to use muscular effort to hold the rifle up.
Prone: view the position as a tripod (as are all positions, the prone providing the most support). You support the rifle with your non-firing hand and the elbow on the ground is the first point of the tripod, the butt of the rifle is tucked into the pocket of your shoulder and between the two the rifle should sit there naturally. The rifle rests on that non-firing hand without excessive grip or effort. Your firing hand grips the pistol grip and will operate the trigger. The elbow on the firing arm  is the second point of the tripod. You should be able to take the firing hand off the rifle (for example to work a bolt) without the rifle moving, supported by the non-firing hand and the pocket of your shoulder. The final leg of the tripod is provided by your torso/hips where it touches the ground.
You are gently using the non-firing hand to pull the rifle back into the pocket of your shoulder and other than that there is no excessive muscular force used. 
2) The weapon must point naturally at the target without any undue physical effort: you must set up your ‘tripod’ so that the weapon  points naturally at the correct point of aim. The correct point of aim must be the same as the natural point of aim. The natural point of aim is where the rifle will point if you relax and don’t use muscular force to haul it over in one direction or another. The way you can figure this out is to close both eyes, relax and breath naturally. When you open your firing eye you will see where the sights are pointing. It should be at the target, but probably won’t be! Imagine you are on a pop-up target range out to 300 meters. Targets will come up at various ranges and off to each side of the axis. The lazy thing is to just haul the barrel over each time and  take a shot. The other way you find out your natural point aim is seeing where the sights settle once you have released your shot – unless they settle back on the correct point of aim, your natural point of aim is not correct.
The way to do it is to move your ‘tripod’ so that you are correctly aligned with your target. This means moving your torso/hips, To move your natural point of aim right, move your legs/torso left. To depress your barrel, move your hips forward, to raise your aim, move your hips back. Thus, if you are conducting an application of fire shoot on a pop-up range, you should be moving dynamically with your hips as the targets appear, not just hauling the barrel over with your forearms.
3) Sight alignment (i.e. aiming) must be correct: Before I go into this, note that if you are waiting to engage targets, you should have both eyes open and looking over the top of your sights. To not do so will reduce your awareness of the battlefield and target acquisition. It will also produce tunnel vision, particularly with narrow field of view optics, which will lead to awareness and fratricide problems when you move onto field firing. At closer ranges and also with particular sights designed as such (ACOG etc.) you will engage with both eyes open. As ranges increase, you will move back to your fundamentals and it becomes more like range shooting, closing the non-firing eye to take the shot.
Check the linked U.S. Army Study guide above for diagrams on correct sight alignment. Sight alignment is closely tied in with natural point of aim and breathing. Once you have set up your ‘tripod’ to establish that natural point of aim, you should be breathing naturally. When you do so, the sights will move up and down: as you breath in, the sights will depress (chest rises) and as you breath out the sights will rise (chest falls). See-saw action. The correct time to take the shot is to time it so that as you breath out, the sights rise onto the correct point of aim and you pause to hold your breath to squeeze the shot, then continue. Don’t hold your breath too long, or you will start to shake and it will all go blurry. If you mess up, just keep breathing and try again. Doing it this way, if aiming at a single target to get a group, you can simply breath and take steady shots each time the sights align, thus getting a good group and not disturbing your position.
Note, in the early stages of marksmanship training, its all about getting a good tight group. This indicates application of the fundamentals and will transfer to your more advance shooting in the form of greater accuracy. Target style shooting is the bedrock and tight groups will allow you to move forwards to field firing with better skill. Don’t forget your Appleseed!
Note that your correct focus is not on the rear sight or the target, but on the front sight. You should be focusing on the front sight as you release your shot. If you have a consistent position, cheek weld and thus sight alignment, and you place the front sight on the target as you release the shot, you will not miss.
4) The shot must be released and followed through without disturbance to the position: This means that you will not snatch the shot. There is natural recoil and your body will absorb that. If you have a natural point of aim the sights will settle back into the correct position, you continue breathing, and get ready for the next shot. When you pull the trigger for deliberate shooting like this, you will hold it to the rear until the shot has released, then deliberately let it forward. There should be an audible click as you let the trigger go forward. That is how you ensure you do not snatch your shots.
Application: It is vital that you get a solid basis in this kind of marksmanship training and application of the fundamentals. When you move onto transition to field firing, field firing, reactive shooting and any kind of close quarters stuff, you will not be able to apply the fundamentals in such a deliberate way. But you need them as your foundation.
In a combat environment you will be moving, taking up odd fire positions behind whatever cover is available, breathing hard as you conduct movement on the battlefield. This will make it hard to apply the deliberate principles. You will not have a steady breathing pattern and in a kneeling or standing position you may be simply ‘holding the wobble’ as you take the shot. You may be muscling the rifle around to engage targets. You will not have time to hold the trigger to the rear, you may be firing rapid shots. However, with the fundamentals behind you and a good natural position on the rifle, you should be able to bring it, with practice, into a better natural aiming position and have a better chance of getting off accurate shots.

There is more on the combat side of this in my previous post HERE: Combat Rifle – Solid Basics to keep you Alive
I make it a point of not being an advocate or ‘fundamentalist’ for any of the various styles, alternatives, fads to whatever of shooting positions and equipment, in particular for standing close quarters engagements. I simply advocate that you do what works for you. If you are an old dog, it may be harder for you to learn new tricks, so do what works based on the solid fundamentals. In one of my classes, you won’t be upright for long anyway, you will be taking cover!
Live Hard, Die Free.