The Often Underrated Compressed Air Gun

For homesteaders who want most of the advantages of firearms without owning an actual firearm, the compressed air gun is a viable alternative.


| May/June 1981



069 compressed air gun - spring piston

The spring-piston air rifle is a common type of compressed air gun.

ILLUSTRATION: OUTDOOR LIFE STAFF

All the folks here at MOTHER EARTH NEWS were pleased with the response generated by Gary Kent's article, "Homestead Firearms".  Many readers are interested in having a practical gun on hand to protect their livestock and homes, and occasionally put food on the table, and those readers who aren't interested in owning such weapons don't begrudge others the right to do so.  

Furthermore, a good number of the letters received here asked for more information on firearm alternatives. Well, it would be hard to imagine a more practical tool for such tasks as controlling pests, repelling small predators and putting meat in the homestead freezer than the compressed air gun. Such firearms are often surprisingly powerful (and, therefore, must be handled with the same respect as "real" guns), quite accurate, easy to maintain and extremely inexpensive to shoot. For a total spare-parts-and-ammunition investment of well under $200, you'll be able to add a rabbit to the pot, as times demand, for years to come!  

Spring-Piston Gun

The most common air gun mechanism is the so-called spring-piston type used in millions of American BB guns. Since this basic mechanism is the power source of our simplest, least expensive air guns, one might conclude that it is relatively inefficient. Such is not the case. Essentially the same mechanism is used in the most expensive, most accurate and most powerful air guns. 

In simplest terms, a spring-piston gun is powered by a spring-powered piston that's contained in a closely fitted, tube-like chamber. This chamber serves as the gun's receiver, which is mounted in the stock with the barrel attached to one end and the firing mechanism attached to the other. When the gun is cocked, the piston is forced to the rear of the chamber, where it is held in place by a catch, or sear, linked to the trigger. At this point the mainspring is compressed to full tension.

When the trigger is pulled, the powerful mainspring slams the piston through the chamber, driving and compressing the air in front of it. This body of air escapes through the barrel, driving the projectile.

The relative projectile velocity of a spring-piston air gun is determined by a number of factors, but velocity is mainly a function of the speed and power of the piston and the volume of air displaced. Other factors are the weight and size of the pellet, and the amount of air leakage which occurs around the projectile and piston. Naturally, a projectile which efficiently seals the bore, and a close (but not tight) piston-to-chamber fit are more efficient than tolerances that permit air blowby.

n_3
3/28/2007 8:49:00 PM

Pre charged pneumatics utiising air reservoirs pressurised to 1000p.s.i.are now taking over as hunting air guns of choice in Europe. They are smooth in operation, as powerful as legal limits will allow (and with higher potential) suitable for scoped hunting and generally what you expect a good gun to feel like. They aren't as cheap as traditional spring/piston models but offer a good compromise between air and fire power.


jeff_33
3/8/2007 3:47:56 AM

Interesting article but over and over you refer to airguns as firearms which they are not physically; most don't make any fire but the main point is that they don't ignite combustible material to produce the expanding gasses which propel the projectile down and out the barrel, nor legally, at least in these United States of America. The laws regarding airguns and firearms are different and do not commingle but as time progresses the all knowing government officials continue to try to alter these laws as to blur them into one general classification so to make easier the eventual, outright ban of any gun possessed by the general public. Kind of like what Stalin and Hitler did, you know. The overall ignorance of the people does nothing but promote the agenda of the “gun control” advocate and the eventual progress towards a dictatorship. So please, in the future, educate yourself first, then make clear to your readers the difference between the two. A good initial reference regarding this and many more airgun related topics is: http://www.beemans.net/ Regards, Jeffrey M Dobric






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