I received these tips in a newsletter from Appleseed. I thought I would pass it along. There is good information here.
From an engineering perspective, the prone position uses two rigid triangles to lock the rifle in place: A vertical triangle consists of the sling, upper arm and lower arm, anchored at the elbow. The rifle sits on top of this triangle. Because of the tight sling, the rifle butt is solidly pressed into your shoulder pocket, and the forend is anchored to the palm of your support hand. The horizontal triangle consists of the rifle, your body across the shoulders, and the sling. The taut sling is an element that defines both triangles. This is why keeping the sling loop in the correct position, above your bicep, is critical. If the sling slides down toward your elbow, it becomes loose and also destroys the integrity of the triangles.
Let’s look at the elements of the prone position. As with any system of interrelated parts, an error in any one element causes misalignment or weakness in one or more others.
Angle of the body relative to the line of sight: Try this: stand facing the target directly. Your shoulders will be far apart as seen by someone at the target, and your support elbow can’t possibly reach close to the rifle on the trigger side shoulder. You will have to lean your head pretty far over to put your cheek on the comb. If you turn toward your trigger side, your shoulders are closer together from the target’s perspective and it’s easier for your elbow to reach under the rifle. The stock is now directly under your cheek, next to your neck. This is illustrated by the crude drawing below the article.
What is the correct angle for your body relative to the target? This will be largely determined by the width of your shoulders and the length of your arms. There are two considerations here:
• One is that you want the comb of the stock directly under your cheekbone so that you can lower your head without tilting or stretching out to reach the stock, and get the perfect cheek weld and sight alignment. If you have to tilt your head to the side to reach the comb, the stock is too far out.
• The second is that you want your support elbow directly under the rifle, and the support forearm in line with the rifle. This position supports the weight of the rifle directly through your bones to the ground. If your elbow is off to the side, you will need to use the muscles in your arm and shoulder to hold it in position. Though the tight sling helps, it isn’t perfect and some effort is required. You can often tell if a shooter’s elbow is off to the side by the group pattern that arcs downward towards the right (left for a left-hander) as the shooter gets tired while shooting the stage. You can tell if your elbow is correct if the muzzle moves exactly vertically as you breathe and during recoil. You can also tell by checking your NPOA (put the sights on the target, close your eyes, then breathe and open your eyes – the sights should still be on the target). Note that you want the flat area above the point of the elbow to be on the mat. As with sitting, you don’t want to try to balance on the point of the elbow. To get the elbow under the rifle, you need to extend your support-side shoulder toward the rifle and “invert” the elbow so that the forearm is in line with the rifle.
Once you have the correct angle, you can use your shooting mat as a reference to remember it. Many beginners place the mat quite straight on to the target, and lie at an angle across the mat. It works much better to move the mat to the correct angle and always lie in line with the mat. Once you have the angle that works for you, you can draw an arrow on your mat parallel to the rifle’s line to the target. (For an erasable arrow, mark it with a strip of tape rather than a pen.) When placing your mat on the firing line, stand behind it and sight down that arrow straight to your target.
Support arm angle: The angle of your support arm at the elbow determines the strength of the vertical triangle that holds the rifle steady against gravity and recoil. If the arm is too straight, the sling will pull down along your upper arm rather than across the humerus bone. Raising the forearm to at least 30 degrees above horizontal is usually required for the sling to do its job. Depending on the height of your shoulders or your arm length you may need a higher angle.
Support hand position then becomes an issue for most of us. NRA smallbore and ISSF (Olympic and World Cup) rifles have rails on the forend to adjust the sling attachment point to be used as a stop against which the support hand rests. The rest of us, with commercial or service rifles, have to deal with the standard swivel position which is often too far forward for many of us. Without a hand stop, how do we prevent our hand from sliding down the stock? I find that with the sling length and tension just right, the wrap of the sling on my forearm locks my hand in place on the stock. If the sling is too loose, it doesn’t support the rifle and I can feel my bicep flexing to hold the rifle up. If the sling is too tight, my arm is forced into a low, straight position that provides no support and allows the sling to slide down the arm. So you want to adjust both hand position and sling length to find the right balance. You may want to mark your sling so that you can easily set the right length, and put a bit of tape on the stock to mark your hand position.
Shoulder height and orientation, and buttstock position: Your shoulders should be nearly level, and your head fairly erect. The rifle butt should be solidly in the upper part of your shoulder pocket. To see how this works, watch some trap shooters mount their guns. They point the shotgun upward to place it near the top of the shoulder pocket, and then lean their upper bodies forward into shooting position. In prone, our entire body is leaning forward in the shooting position. What we consider “the pocket” in standing is now facing downward, so putting the butt there will allow the rifle to slide down the chest rather than being held solidly between the shoulder and collarbone. With the rifle seated correctly in the pocket, as you relax you can feel your body push the rifle forward to tighten the sling.
If your shoulders are too low, or if you put the rifle butt too low in your shoulder, you will be craning your neck to look “up” at the target, or looking through the top of your glasses at the rear sight. You should be able to see through the center of your glasses without straining your neck. Move your support hand back on the rifle stock (adjusting the sling length if needed) and check the butt’s position in your shoulder to raise the rifle and your shoulders for a more natural head position.
Trigger-side arm: The trigger-side arm is a critical element of support for your horizontal triangle. The humerus bone running from shoulder to elbow bears the weight of the rifle and your upper body. This bone needs to be fairly vertical to plant the elbow solidly and bear weight. If this bone is too horizontal, either to the side or forward, your shoulder muscles will have to work to hold the arm in place and prevent your elbow from sliding on the mat. Of course, this is bad. I once had a student whose string of five shots started in the 10-ring and made a straight line towards 10:30 ending in the 5-ring (on an NRA 50-foot smallbore target). Her trigger-side elbow was sliding sideways on the mat with each shot. Also, if this arm placement holds the shoulder too low, your shoulders will tilt causing the rifle to cant.
The fit of your rifle, specifically the length of pull (distance from butt to trigger), will affect the stability of your trigger-side arm. If the LOP is too long, you will extend the elbow forward to reach the trigger. Junior shooters often struggle with full-size rifles because both arms are extended too far forward, which destroys the triangles and lowers the shoulders. You can check your rifle’s LOP by placing the butt on the inside of your elbow and reaching your finger to the trigger. The first joint of your trigger finger should easily reach the front of the trigger blade. If it doesn’t, you should modify your stock or install an adjustable stock.
Trigger-side knee: Pulling this knee out and up toward the hip has three positive effects. It makes a large triangle of your lower body that resists rolling sideways – you are now stable both fore-and-aft and side-to-side. It puts a flatter part of your abdomen against the ground (especially if, like me, you like to snack during football season) and gets half your diaphragm and chest off the ground so that breathing is easier and affects the rifle less. Finally, it raises your trigger-side hip off the ground, causing a slight rotation of the spine that makes it easier for your support-side shoulder to extend towards the rifle to properly locate the support elbow.
Relaxed position: Many shooters seem to believe that they must hold the rifle with their arms and pull it into the shoulder. This is actually the opposite of what we should do. In a good position, your body and arms are fully relaxed and the taut sling is what pulls the rifle butt into your shoulder pocket. Imagine yourself as a water balloon on the mat. When you relax and allow your body to settle, your weight presses the shoulder forward against the rifle to put the right tension on the sling. Now the sling is pulling the rifle into your shoulder, your bones are supporting all the weight, and your arm and shoulder muscles don’t have to do anything at all.
Putting it into practice: It may take some experimentation over time for you to refine the elements of your prone position to achieve that solid, relaxed NPOA. Fortunately, with dry-fire practice you can do this at home without wasting a single cartridge or going outside in bad weather.
It doesn’t have to take much time to perfect your position. An efficient way to find the sweet spot for each of the above elements is to use the “bracket” method. Exaggerate your first adjustment beyond what you think necessary. If it’s too far, you know the solution is between those two points.
Remember, if you aren’t comfortable, your position still needs adjustment and you must make changes to get it right. Doing the same things but trying harder will not work. Keep trying different adjustments until you can easily relax into position with your sights on the target. Like riding a bicycle, once you “get it” you will find that it just feels right, and it will be easy to repeat consistently. Before long you will be able to align the mat and automatically settle into a solid position with NPOA every time. Now you can use your prep period to place that NPOA precisely on the target and make tight groups in the V-ring on your AQT.