This is the most basic safety rule.
NEVER POINT THE MUZZLE AT ANYTHING YOU DO NOT INTEND TO SHOOT!!!
It's as simple as that, and it's all up to you.
Rule No 2
ARMS SHOULD BE LOADED ONLY WHEN IN A SHOOTING RANGE. UNLOAD IMMEDIATELY WHEN YOU HAVE FINISHED SHOOTING.
Never assume a gun is unloaded.
Rule No 3
NEVER RELY ON YOUR GUN'S SAFETY.
Treat every arm as though it can fire at any time. Never touch the trigger until you actually intend to shoot!
Rule No 4
BE SURE OF YOUR TARGET AND WHAT'S BEYOND IT.
Never shoot unless you know exactely what your shot is going to hit. Be absolutely of your target and where your shot will stop.
Most Common Types of Airguns and Calibers
Pre-charged pneumatics use a large air reservoir of highly pressurized air, which results in many shots before needing to be recharged. Recharging is a simple matter, either with a high-pressure hand pump or a SCUBA tank. These guns have many advantages, they are extremely powerful (the most powerful air guns made are pre-charged pneumatics), very accurate and most are made of high-quality parts and craftsmanship. The only real downside to most pre-charged air guns is the cost of the gun itself and the initial investment of a SCUBA tank.
Most PCP airguns here in Malta are un-regulated, which means that when the rifle is filled with air to it's rated maximum fill pressure, the rifle will show a gradual rise in muzzle velocity with each shot as the valve gets into its best working pressure range. The muzzle velocity should then level out through the Heart Of the Fill finally tailing off as the rifle runs out of air.
Definition of the Heart Of Fill
The Heart of Fill is the combination of initial fill pressure and number of shots that produces the most consistent practical shot string. It's the best trade off between the number of shots per fill and consistent muzzle velocity. It's choice is subjective, depending on the range to target, muzzle velocity and pellets used.
To find this area the gun is filled to full pressure and shot over a chronograph. The shots are counted, velocities recorded and the graph plotted. The pressure at the end of the test is recorded and subtracted from that of the beginning. This number is divided by the number of shots and the result is approximately the amount of pressure per shot that the reservoir diminishes. The gun will now be charged to the pressure where the graph starts to flatten and shot to where the graph starts to drop off.
Spring Piston Air Rifles
Spring piston airguns are probably the most common air guns. They utilize a stout spring and air piston to propel a pellet down range. The operation is actually very simple, for each shot the spring is retracted and when fired, the spring pushes the piston forward, propelling a charge of air into the barrel. These types of air rifles are very consistent on a shot-to-shot basis, can be very accurate and sometimes very powerful when kitted up. While the spring piston is the propulsion method, there are several types of cocking mechanisms, such as a break barrel, side-lever and underlever. All methods essentially do the same job, with a different placement of the lever, however, it should be noted that certain designs such as side-lever cocking and underlevers are slightly more accurate than break barrel cocking models due to their longer sight plane and stiffer barrel-to-action mating, but for hunting and general plinking the advantage is not significant enough to make much of a difference.
Air Rifle Calibers
Over the years, air rifles have been produced in literally dozens of calibers, and while there are manufacturers that still produce custom calibers for specific purposes, the vast majority of air rifles manufactured today come in one of four common calibers: .177, .20, .22, .25.
By far the most common of these four is the .177 caliber. This caliber is the same diameter as a steel BB and many guns chambered in .177 can fire either BBs or pellets. The .177 is an excellent target caliber and also serves well for shooters interested in cost effective plinking. The .177 caliber also boasts high velocities, good penetration and a flat trajectory.
The next most common caliber is the .22. The .22 is primarily used for small-game hunting and is an efficient caliber for delivering energy downrange due to its heavier pellets, however due to lower velocities it is not as flat shooting as the speedier .177.
The .20 caliber is probably the third most common air rifle caliber. While it is not as popular as either the .177 or the .22, it is an effective caliber in its own right. Most .20 caliber air rifles have high velocities, flat trajectories and enough downrange energy to make them a highly effective small-game hunting tool. Many proponents of the .20 feel it is the perfect air gun caliber, boasting of the best characteristics of velocity combined with energy of both the .177 and .22.
The least known of the four common air rifle calibers is probably the .25. However, it is a substantial small-game hunting caliber and carries a lot of energy downrange for quick, humane kills. Since the velocity is slower than all of the mentioned calibers, it has a more loopy trajectory, but within reasonable ranges.