By ADC Instructor Jeremy Decker
Precision rifle shots can be taken from a variety of field positions, however, it is widely accepted that shooting from prone offers the most stability, it’s also typically the first position used while learning scoped-rifle craft. What makes the prone position most stable is its low center of gravity and maximum contact with the ground for both the rifle, and the shooter. The most stable geometric shape is the triangle; therefore, the rifle is most stable when it has 3 solid points of contact with the ground. The front of a rifle supported by a bipod creates 2 of these points of contact. Stabilizing the rear of the rifle when shooting from the prone position can be accomplished in a number of ways; but is made much easier with a physical support of some kind, such as a “rear bag.”
There are a few basic types of rear bags, along with various shapes and fill materials. Commercially manufactured bags can be found in shapes such as cylinders, wedges, flat squares, or bone-shaped bags. Some shooters prefer a larger rear bag that serves as a solid rest for the rifle, while others prefer a smaller, more adjustable set up like a “squeeze bag,” that allows the shooter to make fine adjustments to their elevation by increasing or decreasing their grip on the rear bag. There are even more complex designs that pump up with air like a blood pressure cuff to accomplish this same effect.
The filler material in commercial bags typically consists of plastic fiber fill, poly beads or other lightweight non-absorptive material, but some bags can also be filled with rather heavy materials primarily used when shooting from benches, or at least when carrying a lot of gear isn’t a concern. There are also “sling bags,” or small bags that attach to the sling or rear of the stock so the shooter can keep a small bag attached to the rifle all the times.
Homemade bag shapes are typically cylindrical or tube-like with the wedge shape being popular as well. Homemade bags can be improvised out of all kinds of items, there are even some adventurous shooters who take it out on their wife’s sewing machine; stitching up replicas of current designs or making their own truly custom shapes. The materials for the bag itself are typically nylon, cotton, denim, or some other durable fabric. Sometimes old socks are used to produce a workable rear support -and there is nothing wrong with that, as long as all of the holes are sewed up to prevent the fill from leaking out.
Homemade bags are usually filled with sand, rice, dried beans, popcorn, paper, gravel and other materials. If it isn’t going to be used in the rain, almost anything will do, but if grain fillers like corn, birdseed, beans, or rice are used, keep in mind they can swell up, get moldy, or even start to sprout if they get wet. They can also attract vermin that will chew holes in your rear bag looking for a quick snack.
In addition to using bags as support for the rear of the rifle, larger bags can be used to fill in any open space that will give the shooter a more supported position. Other uses for bags include using them as a soft rest for the rifle forearm on potentially awkward or jagged surfaces like rocks. Bags are very helpful when using shooting sticks, they help to spread out and stabilize the sticks, as well as creating a surface that will allow the rifle to easily pan and cant without disturbing the sticks, and absorbing a great deal of bounce when the rifle fires.
While a rear bag can be a big help, one can mimic the stabilizing effect of a rear bag by using the support hand beneath the buttstock, either flat or balled up into a fist. Different strokes for different strokes but when a quick shot is needed it’s a viable technique.
While many people are looking for the “one” rear bag, like so many things in life there is not one size that fits all. My personal preferences for rear support are the cylinder shape I improvised from an old Crown bag, or the small wedge-shaped bag that was custom made for me by fellow ADC instructor Rowland Rivero. When shooting from hard surfaces either a flat bag or bone shaped bag get used the most.