Setting Up a Long-range Air Rifle

I have been hunting with airguns for more than 30 years and have mostly considered them a close-range tool. As a matter of fact, it is the challenge of getting in close and picking the precise shot placement that is at the heart of airgun hunting for me. However, there are situations where it is necessary to reach out farther.

When discussing long-range centerfire rifles for prairie dog shooting, it is in the context of 400 yards or more. But airguns operate at lower power outputs and with lighter projectiles, and long range for these guns is in the 100- to 150-yard parameter. It is possible to reach out farther, especially with some of the big-bore airguns, but for a .22- to .30-caliber rifle designed for pellets or airgun slugs, 100 to 150 yards is a viable and achievable goal for consistent and effective pest control.

I recently set up two guns for prairie dog and groundhog hunting, with a focus on selecting the best projectile for 100 yards and optimizing the power settings and ballistic performance for that distance. I also wanted to select stocks and air supplies that would support long-range shooting, with optics designed to yield the best performance in the field.

The two platforms selected for this project were the Hatsan Factor Sniper Long and the Air Venturi Avenge-X tactical rifles. Both are precharged pneumatic (PCP) air rifles sharing some common traits that I wanted for long-range sniping; both are regulated and provide highly adjustable power control; they have large volume air supplies that charge to pressures over 4,000 psi and have ergonomic and adjustable stocks. I also wanted guns that cycled smoothly and were easy to actuate, with a trigger that could be set to my preference.

Setting Up a Long-range Rifle

Let’s start by looking at my rifles of choice, their core feature sets, how I dialed them in for long-range shooting, the projectiles used, the optics and how they performed. After that I’ll share some of my thoughts on using these guns — what worked and what I might change in the future.

The Hatsan Factor Sniper Long rifle is purpose built for long-range accuracy — primarily for competitive precision shooters. Available in several calibers from .22 to .35, I opted for the .25-caliber. The performance of the Factor can be adjusted via an externally accessible hammer preload control and an adjustable regulator. Onboard air storage is a 700cc carbon fiber tank with a large 100cc plenum and adjustable regulator that allows the gun to generate consistent shots at high velocity while optimizing air usage. I set my gun up to shoot JSB Diabolo Exact King Heavy 33.95-grain pellets at about 940 fps and was getting 17 shots before having to top off the tank.

The gun has an ergonomic and smooth side lever cocking action, which actuates a high capacity 19-shot magazine. The match trigger is an adjustable design that permits the travel, second stage engagement and pull weight to be individualized. I have it set up with limited pre-travel, a crisp break at 1.4 pounds and no over travel. The trigger shoe can be adjusted vertically and horizontally, and I set it to fit the pad of my trigger finger perfectly.

The stock is a Mil-Spec configuration with an integrated folding monopod and adjustable cheekpiece and buttpad. The aluminum frame has a Picatinny rail incorporated into the forestock, and using the monopod with an Acu-Tac FC-4 mounted on the forestock, this rifle is great for shooting prone when I’m out after prairie dogs.

The only critique I could level is that the Factor Sniper Long is on the heavy side; however, this is part of the reason why this is a stable platform. I chose this rifle for a very specific application, and while it is not the best option to carry through the woods on a squirrel hunt, it is just about perfect for 125-yard prairie dogs out on the wide-open grasslands.

I chose the .25-caliber Air Venturi Avenge-X for this project because the modular design allowed me to select the exact components I wanted. The parts list includes barrel kits, probes and magazines for .177-, .22-, and .25-caliber. There is also a selection of stocks, including tactical, bullpup and a more traditional sporter style in hardwood or synthetic material. I opted for the tactical stock with an AR-style pistol grip, the longer shrouded barrel and for air storage went with the 400cc carbon fiber tank rather than the 200cc reservoir tube used for my carbine version of the gun. As with the previous rifle, there are two pressure gauges incorporated to monitor tank pressure and the regulator pressure.

The Avenge-X performance is optimized via a hammer spring adjustment screw, a two-position transfer port and adjustable regulator. I adjusted my rifle to handle both JSB Diabolo Exact King Heavy 33.95-grain pellets and NSA .25-caliber 29.5-grain slugs using the same settings. When switching between these projectiles I need to adjust the scope, but the same power setting works fine. This setup generates about 900 fps for the pellets and about 925 fps for the slugs, with slightly better accuracy obtained with the pellets unless the winds kick up. Then the slugs have a flatter trajectory and seem to be less affected by wind drift at greater distances. The regulator can be adjusted up to 3,000 psi, so it is possible to dial it up for increased power, though my focus is the best 100-yard accuracy.

This rifle is cycled with a side lever action that actuates the 13-round magazines and a two-stage adjustable trigger that is set at about 2.5 pounds with slight take up, a clean break and a little bit of over travel. The synthetic tactical stock utilizes an AR-style buttstock and an AR-compatible grip. There is an under forestock Picatinny rail that is often equipped with a UTG Recon 360 TL bipod when shooting prone or off the bench. But this gun is very stable and comfortable when shooting from a sitting position off sticks. Of these two rifles, the Hatsan is slightly more accurate, however the accuracy of the Avenge-X is very good, and the gun is a lot easier to carry when I’m on the move through a prairie dog town.

When optimizing the guns’ performance there are a few possibilities. The first adjustment is the transfer port, which directs compressed air from the plenum to the rear of the projectile and propels it out the barrel. Altering the shape or length of the port can alter performance. The function of the regulator is to set the operating pressure for the valve, ensuring that it is the same for each shot. For example, if the regulator is set at 2,400 psi, each shot will be at 2,400 psi of pressure even if the air storage tank is 4,500 psi. This setpoint does not allow the pressure in the plenum — the smaller chamber between the regulator and the valve — to exceed that (2,400 psi) setpoint.

The result is that the variation from shot to shot is minimized, and the accuracy is increased. But the optimal operating pressure setting is also dependent on other variables, including the projectile being used, and requires testing with a chronograph to optimize. The hammer spring determines the force hitting the valve, and an adjustable hammer spring allows the shooter to define how much energy is used to open the valve. All these together allow the gun to be optimized for a specific projectile or range solution

Preferred Projectiles

In the past, airgun ammo consisted of Diabolo-style pellets, typically designed with a skirt, narrow waist, and a head that was rounded or domed shaped, hollow point or a flat head or wadcutter. These work well out of most air rifles, providing accuracy and good terminal performance. More recently airgun specific slugs in standard calibers (.22-, .25-, .30-, .35-caliber) have become available. In my earlier experience with many of these slugs, some guns digested them well and provided great accuracy, but conversely a lot of rifles printed groups that looked more like a buckshot pattern. However, with the power adjustments mentioned above, guns can often be set up to shoot slugs very accurately.

Some platforms offer a barrel specifically engineered for airgun slugs, but my anecdotal observation is that the typical 1:17 twist rate used for .25-caliber airguns works well for both pellets and slugs, so long as the power output can be adjusted. What I think is more important for slugs is to have an unchoked barrel.

The advantage of slugs for long-range shooting is they are ballistically superior to the Diabolo pellets, are flatter shooting, and I believe are less sensitive to wind drift. They also provide excellent terminal performance with a balance of energy delivery and penetration. Pellets, on the other hand, are like bumblebees — they shouldn’t fly as well as they do. They can be quite accurate but tend to shed velocity more rapidly than slugs with a more pronounced trajectory, are more influenced by wind and offer perhaps a little less effective terminal performance. However, they perform well in most guns, are less expensive and provide a wider selection to choose from. I use both for long-range shooting, but still do not have a clear preference.

Airgun Optics

I use a lot of different scopes on my long-range airguns. Some favorites are the MTC King Cobra FFP, Element Titan and Hawke AirMax. My preference for topping these guns is magnification in the 4-24X range, a medium fine crosshair and uncluttered reticle with well thought out aimpoints and high-quality glass.

I carry a rangefinder for long-range shooting of prairie dogs, groundhogs, etc., so don’t typically use my scope for ranging shots. I also don’t typically use the scope adjustments to make corrections in the field, relying on Kentucky windage. I find that in the gusty winds often encountered out on the open prairies, you can end up chasing your tail when trying to dial the scope in. Shifting the crosshair left/right, or changing holdover works better for me.

Do Your Homework

I’ve given a couple examples of airguns I selected for long-range shooting, my requirements and preferences, how I set them up and the projectiles I shoot. But there are many other guns that make very good long-range shooters. I have a BRK Ghost in .30-caliber and an FX Impact (.25- and .30-caliber) that are tackdrivers, though they cost two to three times the price of the Factor Sniper and the Avenge-X tactical rifles. That is another aspect to consider, but both guns I presented are more affordable, and provide great platforms for learning how to get the most out of a long-range hunting rig.

Because airguns operate at lower power/velocities than firearms, the trajectory is more impactful at closer distances and shooting a .22- or .25-caliber air rifle at 100 yards feels equivalent to a centerfire at 300 to 400 yards. Shooting a prairie dog at 125 yards with the intent of dropping a pellet or slug right between the eyes, rather than a centerfire exploding him with a center of mass shot at 300 yards, you understand this is long-range precision shooting!