Harpenden Air Weapons Club
Types of Air Guns for Paper Target Shooting.
Target Air Rifles and Air Pistols are of similar design. Rifles have longer barrels, longer bodies and are mounted on a piece of wood called a "stock" which is held against the shoulder, whereas pistols are fixed to a wooden "grip" held in one hand only.Spring Powered.
The classic basic airpistol has a
spring which pushes a piston, rather like a bicycle pump, and creates
pressure to push the pellet along and out of the barrel. The heavy piston
as it moves imparts a strong recoil on the gun and the barrel will jump
and accuracy is compromised. A Webley Tempest for example would not be
used for serious target use. On a target quality pistol or rifle, a heavy
part of the mechanism is allowed to move in the opposite direction to the
piston to counteract the recoil. This is usually either an identical
piston linked with a rack and pinion to move in the opposite direction,
or else the barrel and part of the weapon is allowed to slide backwards
on a sled at the time of firing, like the barrel of an artillery
gun.The Feinwerkbau 65 pistol (sled type illustrated here) and 300S rifle, and the Original model 10 and model 6 (rack and pinion counter piston) are by far the most commonly used of the spring pistols.
Single-Stroke Pneumatic.
This kind of
airgun is pumped once by hand for each shot. Pulling the trigger releases
a small spring-loaded weight which hits an air valve with a consistent
velocity, releasing a measured shot of air. As there are few moving parts
at the time of firing there is almost no recoil. Some strength is
required to pump it. Pardini K58 illustrated here.Compressed air, or Carbon Dioxide.
This uses
similar firing mechanism to pneumatic, except it carries its own supply
of compressed air in a cylinder, typically 2000 - 3000 p.s.i, or liquid
carbon dioxide which is at a rather lower pressure. Compressed air is
either pumped in before the match using a special stirrup pump, or
decanted from a diver's SCUBA tank. CO2 is usually decanted from the type
of gas cylinder typically used in fizzy drink machines or beer kegs.
Feinwerkbau P40 illustrated here.
The complexity of a modern compressed air gun can be seen with this Feinwerkbau P34 which is my pistol of choice.
A small squarish firing weight is released by the trigger and hits a small valve plunger that allows a measured charge of regulated pressurised air to access the barrel just behind the pellet. Adjusting the spring pressure behind the weight will alter the power approximately 10%. A cylindrical weight near the top of the gun acts to reduce the small amount of recoil. Working pressure is about 100 x atmospheric pressure (100 Bar) which is about 1500 PSI. Cylinder is charged at 200 Bar. Pellet velocity is 450 ft/sec giving power of about 3.5 ft lbs (UK max for pistols is 6 ft lbs, typical Webley Tempest is about 2 ft lbs)
Typical compressed air target rifle of 2007
Sight Pictures
When you look down the sights of a target weapon they look like this. On the left is the pistol sight picture. Note that only the foresight is in focus, and is held just below the aiming mark on the target, The rifle sight picture is more obvious, being concentric arrangement of peep-sight, fore sight and aiming mark
