Air rifle tuning will ensure your gun shoots more accurately, is more powerful, and has a longer lifespan. However, there are many variables when it comes to learning how to tune an air rifle.
In most cases, the tuning process depends on the type of air gun you own. It can be as simple as adjusting some of the settings built into the rifle, or as complex as making hard modifications from swapping parts to machining original parts to meet your needs.
In this air rifle tuning guide, we'll be focusing on the Marauder air gun and how an advanced shooter can tune theirs. Here are some tuning tips to ensure your air gun performs at its best.
First, Disassemble the Air Gun
To get started with air rifle tuning, first remove the stock from the action. This will give you access to all the moving parts so that you can tune, clean, and lubricate them. Tuning requires patience and a keen eye for detail, so take your time to get familiar with all the parts before getting started.
WARNING: ATTEMPTS TO MODIFY THE AIR GUN IN ANY WAY INCONSISTENT WITH THIS MANUAL MAY MAKE YOUR AIR GUN UNSAFE TO USE, CAUSE SERIOUS INJURY OR DEATH, AND WILL VOID THE WARRANTY.
Adjustments in the Trigger Group
Some trigger assemblies can be adjusted and customized, but unless you are experienced in making such adjustments, we recommend that adjustments to factory settings be made only by a qualified gunsmith after reading all instructions. Adjusting the trigger assembly can result in a light trigger pull, decreased sear engagement that could make the air gun more susceptible to discharge when dropped or jarred, or a non-functioning safety. Make only the adjustments identified in your air gun’s owner’s manual.
The trigger group is one of the most important parts of an air gun, and it's also one of the most commonly overlooked when it comes to learning how to tune an air rifle. A well-tuned trigger group can make a significant difference in the accuracy and performance of your air gun, so it's important to take the time to do this air rifle tuning step properly.
A few different parts of the trigger group can be tuned, but the most important is the sear. The sear is what actually releases the cocked hammer or piston in order to fire the air gun, and if it's not tuned properly, it can cause misfires and inaccuracy. With most air guns, there is a hammer of some sort that gets cocked back and strikes the valve stems to release the air held in the valve and reservoir. For a break barrel, the piston is cocked back and once released the quick motion of the piston flying forward rapidly creates pressure in the compression tube which propels the pellet down the barrel.
Here are examples of air rifle tunings for the Marauder:
- For the trigger pull, use a 1/8” Allen wrench to turn the adjuster screw (A) to the right to increase trigger pull weight and turn it left to decrease trigger pull weight.
- For the trigger position, use a .050” Allen wrench to adjust the trigger position at rest. Turn screw (D) to the right to move the trigger back and turn to the left to move the trigger forward.
- WARNING: This adjustment can affect sear engagement and can allow the gun to fire when dropped or jarred.
- For trigger stages, use a .050” Allen wrench to adjust screws (B) and (C) and make changes to the trigger motion position and the length in the first and second stages. WARNING: This adjustment can affect sear engagement, and can allow the gun to fire when dropped or jarred.
- Screw (B) alters the first stage. Turning screw (B) to the right will increase the length of the first stage and decrease the sear engagement. Turning it to the left will decrease the length of the first stage and increase the sear engagement.
- Screw (C) alters the second stage. Turning screw (C) to the right will cause the second stage to occur sooner while turning it to the left will cause the second stage to occur.
- Adjustments of screws (B) and (C) should be done simultaneously with each other.
After tuning your trigger, you should always check that the trigger and safety are functioning properly. If you are unsure if the trigger or safety is operating correctly, take your gun to an experienced gunsmith. If everything is working correctly after this air rifle tuning step, you should notice a significant improvement in accuracy and performance. Check your owner's manual for instructions on how to adjust the trigger of your air guns.
NOTE: these adjustment features are for advanced shooters. Most shooters can use the settings provided during manufacturing of the gun and should not need to make modifications.
WARNING: ADJUSTMENT TO THE TRIGGER ASSEMBLY COULD ALLOW THIS AIR GUN TO FIRE IF DROPPED OR JARRED, WITH OR WITHOUT THE SAFETY ENGAGED.
Adjust the Hammer Spring
When it comes to learning how to tune an air rifle, you'll also want to learn how to adjust your air gun's hammer spring, which controls how hard the hammer strikes the valve. This will determine how much power your gun has and how accurate it is. To adjust the hammer spring:
- Start by removing the stock from your air gun.
- Then, remove the screws that hold the action in place.
- Once the action is removed, you will be able to see the hammer spring.
- Then, use a small wrench to turn the adjustment screw clockwise or counterclockwise until you've reached the desired tension.
- Check your velocity and continue making adjustments if necessary.
- Once you're happy with the tension, replace the action and screw it back into place.
For this air rifle tuning step, you should know that more spring load means you hit the valve harder and open the valve more or longer, increasing your velocity/power. However, there needs to be a balance, as you eventually get to the point of diminishing return and start to waste air and reduce your shot count.
Change or Tune Fixed Springs
For air guns that don't have the ability to adjust the hammer springs, your only option is to change out the spring for a weaker or stronger one. This is a more difficult task than adjusting an adjustable spring, but it can be done. You can also cut down the original spring to get it to a specific tune you're looking for in your air rifle tuning.
WARNING: ATTEMPTS TO MODIFY THE AIR GUN IN ANY WAY INCONSISTENT WITH THIS MANUAL MAY MAKE YOUR AIR GUN UNSAFE TO USE, CAUSE SERIOUS INJURY OR DEATH, AND WILL VOID THE WARRANTY.
Adjust the Valve or Transfer Port
The last tip in our air rifle tuning guide is to adjust the valve or transfer port. Some PCP air guns have valve or transfer port adjustments that control airflow from the valve to the barrel. You'll need to first identify the port to get started with this adjustment. On most air guns, the transfer port adjustment is located on the side of the action near the breech (chamber).
Read your owner's manual to understand how you can adjust the airflow of your air gun. Just like other air rifle tuning adjustments, make small adjustments until you find the sweet spot for your air gun.
- A wide-open valve or port obviously gives you the most velocity/power.
- You can also restrict the air to reduce your velocity/power in order to be more efficient with air consumption which increases your shot count.
For instance, the Marauder air rifle has a small valve metering screw that chokes the air right at the valve exhaust, while rifles in the Craftsman Collection have knobs on the side of the breech that allow you to choke the airflow right at the transfer port. Other air guns that do not have simple air rifle tuning adjustments require hard modification, like swapping out transfer ports to drilling out larger holes into the valve and barrel to achieve the power you want.
Learn More at Benjamin Airguns
By following these advanced steps on how to tune an air rifle, you'll be able to tune your Marauder air gun for optimal performance. Remember to lubricate your air gun regularly and adjust both your valve spring and hammer spring tensions as needed. With a little bit of care and attention, you can keep your air gun shooting accurately and powerfully for years to come.
Learn more about air rifle tuning on our Benjamin Airguns blog. We have more tips and guides to help you get the most out of your air gun. And, be sure to check out our selection of high-quality air rifles, ammo & air, and accessories. Get a Benjamin and make it yours.