Last year I wrote an article regarding slings that I think will be helpful here, below are some excerpts where I'm discussing some of the different techniques that can be used with a sling. Everyone is going to have their preference for different brands of sling and a lot of it comes down to what you plan to use it for. The sling that I use for my carbine isn't going to be the same one I use for my bolt gun.
I believe the best place to start talking about how to use a rifle sling as a shooting aid is to look at some of the slings that are designed just for that purpose. For better or worse, modern precision rifle slings can trace their lineage back to the M1907 sling and the techniques taught by the likes of Townsend Whelen. Sling designs have advanced considerably in 100 years and many now have features that make them versatile and able to adapt to different shooting conditions never thought of before. I'm not going to get too deep into brands but some very good options are from TAB Gear, Rifles Only, Tactical Intervention Specialists, Armageddon Gear, Turner, and others.
Looping Up
Traditionally, using a sling as a shooting aid meant using a loop created by the sling to pass your through and then using body mechanics and sling tension to stabilize the rifle. That's a simplistic way to describe the process but modern slings like the Armageddon Gear sling for example make it easier to utilize this method. The Armageddon Gear sling is fast adjusting because of a Fastex buckle up front so that you can adjust the tension of the sling on the fly to suit just about any position or clothing combination. Looping up in the Armageddon Gear sling is similar to the slings of old, you want the loop as high up on the arm as possible with the strap laying flat across the back of your support hand as you lightly grasp the stock, no need for white knuckling it. When tensioned properly you should be able to drop your strong-side arm, leaving the rifle still supported in the pocket of the shoulder. Bone support is vital using this method and in the sitting or kneeling positions it helps to lean forward to get the shoulders forward of the hips and put your elbow forward of the support side knee. In the field use a rear bag, extra jacket, or even your pack to fill in some of the gaps between your body and the ground. It might take some experimentation to find what works out best for you but something as simple as putting a rear bag under your right foot in the kneeling can make a world of difference.
Across the Back
This method is quick and dirty but it can be used with carbine slings and slings like the ones from Armageddon Gear, TAB Gear, and Rifles only that are fast adjusting and/or have some bungee action to them. It’s effective when you are carrying the rifle in a patrol carry fashion and need some stability quick, fast, and in a hurry. From the patrol carry all you need to do is get into a shooting position, tighten the running end at the front, and let the tension pull across your back to the front of the rifle. I've used this method countless times from a variety of obstacles and not only is it very fast to bring to bear and it's also pretty stable. Personally, I like to use this particular method off of barricades or other obstacles where I may need to move from position to position and I can’t bring a lot of stuff with me. To gain some more stability using this method I also like to push my support arm out, sometimes against the front of the buckle and rotate my elbow inwards slightly to put more pressure on the sling. This helps draw the rifle down a bit more and I've found that it works well to help steady the reticle just before I break a shot. If you are using this method in a standing position, it will help to square up to the target, spread your legs about shoulder width apart, and lock your knees out while leaning forward slightly.
Using this method works in multiple shooting positions, not just the standing but it's pretty effective in the prone, sitting, and kneeling as well.
Carabiner Loop
Some precision rifle slings don't even feature a shooter's loop anymore because outside of some specific circumstances it's even really used. That’s not to say the sling turned back into a carrying strap though, typically they're still fast adjust so there are applicable techniques to get extra stability. Using a tripod to shoot from has taken on a whole new form there’s been a lot of techniques born from that. Some slings feature a built-in loop towards the rear of the sling that can be used to clip the sling to a belt via a carabineer when shooting from a tripod. Once in position the sling can be routed under the legs of the tripod to my belt and then I'll tighten the sling to draw the front of the rifle down into the tripod. Rolling my hips back slightly puts additional pressure on the rifle and helps make the position rock solid. This method can also be applied to shooting off of traditional barricades, natural obstacles, and a host of other situations. At the PRS match I had no issues hitting some targets like a 12” plate at 470 yards and a pepper popper at 400 yards from standing positions using this sling and applying the fundamentals.
Wojcik Method
I first saw what came to be the Wojcik Method in an article by Caylen in one of the first Guns & Ammo Sniper magazines . What I like about this technique is that it’s simple and easy to adapt to multiple sling designs. Essentially, what you are going to do is pull the sling up as high as you can behind the tricep of your firing arm so that it runs from the rear sling swivel around your arm and to the front of the gun. Now, if your sling is adjustable, tighten it up so that you feel the sling pulling the rifle back into your shoulder, for some more tension you can also pull your elbow back if need be. Like I said, this method works across many different slings from precision rifle slings to hunting slings and works great off of tripods, shooting sticks, or even natural obstacles like logs or boulders.
Hunting Slings
Just because most hunting slings are simple carrying straps doesn’t meant that they can’t be used as shooting aids in a pinch. You can easily use the Wojcik technique with a properly adjusted hunting sling or even the trusty hasty sling technique. If you are going to use a hunting sling as a shooting aid my word of advice is to practice with your rifle beforehand so that you know where the sling is adjusted properly and you are used to getting into the position quickly. There’s no metric for what the proper adjustment length is going to be since that is going to vary person to person.
Wrapping it Up…. No Pun Intended
I know I wasn’t able to cover every type of sling but I think I've shown some good techniques to use with a sling. Its effectiveness is going to be entirely up to you and how much you work with the sling to get that accuracy at distance. Simply buying a shooting sling and playing with it once or twice will not make it an effective tool.