So you want to buy an air rifle.
As a relative newbie I won't be presenting the definitive be all and end all guide, but I have been through the whole spiel recently enough to remember and be aware of some of the pitfalls.
Lets start this with a warning. Air rifles are addictive, very addictive. Before you know what's happened you will quite likely have a small arsenal and an irate bank manager or wife.
I have read about so many people who have gone out and bought an air rifle for a specific purpose only to find that what they have bought is totally unsuitable for almost anything at all. I realise that many people only find this forum after they have made their "mistake" purchase and start looking for help. This little oration was written to try and help you make the right choice. I am no genius when it comes to airguns, but I have learned so much from this forum and feel a need to share some of it.
I am not going to cover scopes here at all, they are a separate matter that will need at least as much consideration as the rifle and will be largely dependent on your rifle choice.
The first question you need to ask of yourself is "Why do I want to buy an air rifle (or pistol)?" You need to establish the reason so that you can get something that is fit for purpose and hopefully within your budget.
While pondering your proposed purpose lets look at some basics. Air rifles can be largely separated into two types, springer and PCP.
Springer's have a spring or less commonly a gas ram to drive a piston which compresses the air behind the pellet to propel the pellet. Springers can agin be broken into two basic groups, break barrel and lever. The break barrel is by design less accurate than the lever type because no matter how well made it is, the barrel will never close in 100% the same position every time.
PCP (Pre Charged Pneumatic) has a reservoir of high pressure (typically over 100 bar) air which is released in small quantities to propel the pellet. Most of the other types of airgun are similar to PCP's eg. CO2 driven guns that use a reservoir of liquid CO2.
Some of the advantages and disadvantages of both types are as follows. This is by no means a comprehensive list, but does cover the basics.
1. Self contained
2. Normally cheaper than PCP
2. More difficult to shoot very accurately
3. Inherently less accurate because of the forces generated by the movement of the spring and piston.
1. Inherently very accurate
2. Easier to shoot accurately
3. Easier to make them almost completely silent
1. Need a high pressure air source like a pump or a scuba cylinder.
2. Tend to be more expensive than springers.
How much do you really want to spend? Any pricing mentioned here is based on June 2010 pricing and doesn't include luxuries like delivery. A basic entry level new spring rifle with open sights can be had for as little as R 1110.00 or you could blow the budget of a small country and buy a custom made PCP with all the bells and whistles. I would have saved myself a few rand if I'd known about the R1100 rifles when I bought my son his first rifle and I wouldn't be looking to replace the dirt cheap flea market special he ended up with. For many of us the first airgun is going to be something of a compromise between budget and what we really want. Yes I would LOVE to have an Air Arms Pro-Sport as the springer in my cupboard, but my budget doesn't reach that far. I will however settle for a Weirauch HW97 at half the price or one of MZE's under lever tuned Hatsan's at an even smaller chunk of hard earned. The same scenario exsist's for my choice of PCP. I can't justify blowing R20 000.00 on a PCP, no matter how accurate and powerful it is, so I am saving and looking out for a much less expensive gun.
One of the choices that really has a huge impact on cost is new as opposed to second hand. We all know that new is new, but if I was faced with a choice between a new Benjamin Discovery and a second hand Air Arms S400, provided that the S400 was in good condition it would be an easy choice to make. Keep in mind that the instant you walk out the door with your new air rifle under your arm it has lost value. A good second hand rifle on the other hand should, provided that you look after it properly, keep most of it's value and give you many years of trouble free shooting. If you're unsure of how to evaluate a second hand rifle ask if you can have it checked. Most of the agents will do a check of this nature for a very modest sum. If you're responding to an advert here on the forum, PM one of the moderators, they know most of the scammers.
Be very careful not to fall into the crazy marketing trap of speed (measured in Feet Per Second or FPS). You probably DON'T NEED one of the 1000fps advertised speed monsters. I say advertised speed, because very few of the rifles advertised to be able to achieve that kind of projectile speed can really do so with anything other than special test pellets. On the budget end of the spectrum they are going to be near impossible to shoot even remotely accurately and even the good ones are of little to no use for anything other than long distance shooting. In reality the pellet has not been designed to travel near the speed of sound, so it makes sense to keep the speed under 900fps. The sound barrier varies depending on a number of variables like temperature and air pressure, but is accepted to be around 1100fps. I would rather be shooting fairly accurately at a range of 30-40m with my old BSA meteor at 550fps than not even being able to hit the paper of an A4 target at 20m with one of the alleged 1000fps monsters.
Try BEFORE you buy. Once the money is spent it's spent. I have been very fortunate to have been allowed to play with some other peoples toys while making some of my choices. One of the easiest ways to make new friends and try some different rifles is to attend some shoot's. I would NOT try to bother the guys at a National or league shoot, they need to concentrate on the shoot. Club and fun shoots on the other hand are more fun orientated and the shooters will have more time to talk to you. Keep in mind that most of the members of this forum are really nice people and want to see you buy right first time. I am sure that you would be able to contact a few of the people in your area to arrange an opportunity to be able to try some different air rifles. Even when buying new you should be able to try before you buy. When buying by mail order this obviously isn't practicle. The dealer that won't make a plan for me to have a few shots before I part with my hard earned is going to have to find another way to get my money.
In a nutshell, don't waste your money on a fleamarket Chinese special, for not much more money you can buy a much better rifle that will last much longer and shoot far more accurately. Don't think that you're going to be able to shoot field target competitively with a cheap springer, at the very least you will need a very good under lever spring rifle. That doesn't mean that you MUST get a race gun, some of the Proteas, past and present shoot with a humble AA S400. Trying to shoot FT with the wrong rifle is going to sour the experience for you, nothing is more disheartening than consistently shooting low scores. Attend some shoots and ask advice. Look at what other competitors are using. That counts for all the shooting disciplines.
I hope this has helped even if only slightly. I hope you enjoy your hunt for the perfect collection and may you only buy good guns.
Some useful and interesting links:
More History http://en.wikipedia.org/wiki/Air_gun
Space reserved for a link to a scope choice post.
Note: Feel free to add to the above, as mentioned it is not the definitive guide and I am myself still learning.