To have accuracy with an air gun, you must balance the weight of the pellet to the air pressure that is capable of being produced by the air gun that you are shooting. If the weight of the pellet is too heavy, there will be inaccuracy because there is not enough air pressure to keep the pellet going in a straight line. Conversely, if the weight of the pellet is too light, there will be inaccuracy because there will be too much air pressure to keep the pellet going directly to the intended target. Once you find the pellet weight that balances against the air pressure provided, you will have the “magic” pellet; and you will not only hit your target with predictable accuracy, but you will also find that the penetration is deeper; that is, it will hit harder; and have more knock-down power This is AirGunFu’s Facebook page.
To have authoritative hitting power is desirable for hunting, but for target practice it is only necessary to have enough power to penetrate a piece of cardboard. Most of the high-end 10-meter competition air guns shoot lightweight pellets; yet their air reservoirs can be filled to 3,000 psi. So that they can shoot the lighter pellets, these air guns are equipped with internal air regulators to lower the “working” pressure down to as low as 1,100 psi. By increasing or decreasing the air pressure for a given pellet, it is possible to dial in the accuracy by balancing the pellet weight to the pressure made available.
Some time ago, I was testing a high power air rifle that could be filled to 3,000 psi. In order to achieve accuracy, I had to shoot the heaviest pellet available in the air rifle’s caliber in order to balance the pellet weight to the air pressure out put. All other lighter pellet weights in that caliber were not accurate because 3,000 psi was too much air pressure present for them.
Since the air rifle was not equipped with an internal regulator, I gave it an external regulator by putting one in between the air rifle and my air source: a 4500 psi carbon fiber tank. Using this method, I could keep a constant selected pressure at the air rifle without stopping to fill it.
Taking the lightest weight pellet that I had tested for the air rifle’s caliber, I began feathering down the pressure a little at a time to observe that the accuracy was beginning to come closer and closer. I also “dry-fired” the air rifle several times in between shot sequence to let the pressure settle at each new lower pressure setting.
Once I came to the pressure that seemed to give me the most accuracy with the lightest weight pellet, I lowered the pressure a little more to be sure and the accuracy began to deteriorate. Then, I brought the pressure back up to point where I could predict accuracy with the lightest pellet. Not only did I have another magic pellet, but also I now had a “magic” air pressure.
In order to produce reliable tests, I always lock down the air gun in a gun vise that has the ability to slide back to absorb any recoil produced by the air gun. The slides are simple drawer slides that ride on internal ball bearings for a near frictionless glide. Also a solenoid is used to pull the trigger so that the air gun is isolated to its actual performance and remains untouched by human hands or influence.
I repeated the process of increasing or decreasing the pressure of air for the remaining pellet weights in between the heaviest pellet and the lightest pellet that could be fired in the same air rifle. When I finished with the tests, I had several magic pellets along with several corresponding magic air pressures.
You will be able to find several magic pellets only for air guns that are PCP or pre-charged pneumatic air guns because their air pressure can be adjusted up or down by various methods. On the other hand, spring-piston air guns have only one level of pressure produced by a spring that must be cocked before each shot and no means of adding any pressure from an external source.
In summary, if you experience inaccuracy with your PCP air gun, instead of blaming the pellet try balancing the pellet’s weight to different pressure levels until the pellet becomes indeed another magic pellet.