Elliott on Airguns
Which Airgun Powerplant is Right for You?
by Elliott Jock
All airguns use air (or CO2) to drive a pellet down the barrel, and there are a variety of powerplants that are used to get the air moving. All of them have advantages, and all of them have disadvantages. So which one is right for you? It really depends on which performance characteristics are most important to you. Let's take a look at the different powerplants.
Multi-stroke pneumatic (or pump-up) airguns require 2-8 strokes of an on-board lever (usually the forestock) to store compressed air in the powerplant. Advantages: These guns are virtually recoilless and are completely self-contained. In addition, the velocity of the pellet can be varied with the number of pumping strokes (from, say, 300 fps to 800 fps, depending upon the gun), and the fewer the number of strokes, the lower the noise. Disadvantages: Once a multi-stroke pneumatic is fired, it must be pumped up again.
Single-stroke pneumatic airguns also use a lever to compress air in the powerplant, but require only a single stroke to fully charge the gun. This is the powerplant used on many 10-meter match guns. Advantages: Single stroke pneumatics are fully self-contained, easy to cock, highly consistent and often incredibly accurate. Disadvantages: There is a limit to how much air you can compress in a single stroke. As a result, the power of these guns is usually low, shooting relatively light match-grade .177 pellets at 500-600 fps.
Precharged pneumatic airguns are charged with air from a SCUBA tank or high-pressure pump that is transferred into a small high-pressure reservoir on the gun. Increasingly, high-energy hunting guns, Olympic-quality 10-meter guns, and top-echelon field target guns use this powerplant. Advantages: These guns are powerful, virtually recoil-free, very consistent, and often superbly accurate. Disadvantages: Precharged airguns are generally expensive. In addition, they are not self-contained - you need a SCUBA tank or high-pressure hand pump available to recharge the gun - and somewhat complicated to operate.
Spring-piston airguns - also called "springers" - use a lever (usually the barrel or a lever under or to the side of the barrel) to cock a spring and piston. When the trigger is pulled, the spring is released, pushing the piston forward (and the gun backward) and compressing a powerful blast of air behind the pellet. As the piston nears the end of its stroke, it slams into the wall of air at the end of the compression cylinder and recoils in the opposite direction. All this happens before the pellet leaves the barrel. Advantages: Spring-piston guns are self-contained, often relatively quiet and can be very accurate. Disadvantages: Because their unique whiplash recoil these guns often require considerable practice to shoot them at their highest accuracy. (Note: similar are gas-spring-piston airguns. Instead of a spring, these guns use a "gas spring" which is cocked by a lever and released when the trigger is pulled. The recoil effect is the same.) In addition, the unique recoil of springers demands airgun-rated scopes.
CO2 airguns use 12-gram cartridges, AirSource cartridges or CO2 transferred from a bulk tank into the gun's on-board reservoir. Advantages: CO2 airguns are recoilless, convenient, and (in high quality models) extremely accurate. Noise levels vary from model to model. Cocking effort is usually very low, making these guns a favorite for family shooting. Disadvantages: CO2 airguns require periodic refilling and performance can vary with temperature. Velocity will drop considerably in wintry conditions, and CO2 airguns will shoot faster than normal in very warm conditions.
So which airgun powerplant is right for you? If you want a gun that is self-contained, choose a spring gun, multi-stroke pneumatic, or single-stroke pneumatic. If you want a neighbor-friendly report, a spring powerplant is most likely to deliver it, although you can find relatively quiet pre-charged, multi-stroke, and CO2 models. If you demand the highest accuracy, a single-stroke pneumatic match rifle or a precharged gun is the way to go. If you need an airgun that is extremely convenient to shoot, pick pre-charged or CO2 power. Usually the shortest range airguns will be the single-stroke pneumatics, while some of the precharged rifles are suitable for varminting at rimfire distances. As you can see, no single powerplant type does it all. If you're like me, and the airgun bug bites you, you'll probably acquire several airguns and enjoy the unique advantages of each one.