Spring Air Guns

Spring air guns, sometimes called spring piston guns, have been around for a long time. The guns can be low powered light weight guns like a kid's BB gun or more powerful small game guns which are sometimes physically larger and heavier than some big game rifles.


The firing cycle involves:

• Cocking the mainspring which automatically initiates a trigger safety on many guns.
• The mainspring is inside a chamber much like a simple bicycle tire pump.  
• The safety is released and the trigger is pulled releasing the spring.
• The spring pushes the piston home compressing air in the tube in front of it.
• The compressed air is funneled behind the pellet propelling it down and out the barrel. 

 Like almost everything spring guns have some advantages and disadvantages.

The Good:

• They are generally rugged, dependable, and accurate for thousands of shots.  
• They only require one cocking stroke before firing.
• They are usually quiet with a fairly soft report on firing.
• They are available in all price ranges and can offer good value.
• They are available in many different ranges of power.
• They come in a variety of styles, break barrel, under-lever, side-lever...

Not So Good:

• A dry fire (shot with no pellet) can wreck a spring air gun.
• Cocking powerful guns can require considerable effort, motion, and noise.
• Generally it is considered a bad idea to leave them cocked for long periods of time.
• Many have a strange backward recoil and vibration when fired.
• They may require learning of some new shooting or holding skills for best accuracy.
• The vibration and recoil requires that you use scopes made for spring air guns.
• More powerful guns are larger and heavier due to the need for a larger spring piston.

The gas piston guns or gas ram guns.  These rifles are similar to spring guns in most respects, but they don't use traditional springs. They use a gas or air shock somewhat like the gas pistons on a car's hatch...  

Don't misunderstand you don't fill a tank with compressed air like you do with a pneumatic gun. These guns have a sealed compressible tube of air or nitrogen which is squeezed or compressed with one cocking stroke and then released back to its normal state with the trigger pull.  When released much like a spring gun it pushes a piston which then compresses and pushes air behind the pellet.

Gas ram guns offer most of the spring advantages and less of the disadvantages:

• The gas piston's movement is quicker and has less vibration than a traditional spring.
• Gas piston guns are usually quieter and have less recoil than similar spring guns.
• The gas ram does not take a "set" if left cocked for extended periods of time.
• Powerful gas piston guns may be more compact than similar power spring guns.

I've read and it makes sense that spring piston guns tend to loose power very slowly after years of use and thousands of shots.  Gas piston guns tend to stop working suddenly when they are new or more often last for years and thousands of shots with no loss of power.