Accurate, precise shooting is the goal of any shooter, and few things destroy accuracy faster than instability. A stable shooter can make the most precise shot possible. The closer you are to the earth, the more stable you'll be, and the more surface area of your body that's in contact with the earth, the more stable you'll be. This is why the prone position — laying on your stomach — is preferred by snipers and long-range shooters. It takes maximum advantage of having the earth underneath you and offers maximum stability.
But prone isn't always possible or practical for a variety of reasons. It takes a little time to get into and out of, and if you're faced with an immediate threat like a charging predator, that's time you won't have. And sometimes, particularly in hunting scenarios, terrain and obstacles like rocks and trees might not allow you to get prone and still see the target. In cases like these, the kneeling position is a smart option.
Proper kneeling position is very quick to get into and out of and offers a quick way to get as stable as you can given time and geographic contraints. It also has the benefit of being toolless — no rest or bipod needed, because you're essentially using your own body as a rest. And as Gunsite Academy instructor Il Ling New noted, "we're with ourselves all the time."
Where you place your feet and your elbow and how you balance your weight will make all the difference between a stable kneeling position and a wobbly, unbalanced teeter-totter mess that's no better than shooting unsupported. Watch Il Ling demonstrate the fundamentals of proper kneeling position for shooting.
