I guess everyone else has done a blog on this, but perhaps I can add a slightly different twist to it...
There are many different airgun power plants, each one having it's advantages and disadvantages, and based on those differences, everyone has a favorite power plant. There might be some of you out there wondering what a power plant is, a power plant is the essence of the rifle, it is what controls the air that we use to move the pellet down the barrel and eventually to our intended target.
There are 4 main types of power plants, Precharched pneumatic (PCP), CO2, Single or multi-pump pneumatics, and of course spring. You will find airgun that will fit into many of these categories, and some will fit into none, but those are the ones you will run into most often.
Let's start with PCP, precharged pneumatic gun are my personal favorite! But there are what many people would consider down sides to them. Firstly lets talk about what exactly they are. With a PCP you have a tube(the air reservoir) that holds high pressure air(HPA) at about 3000 psi, some of them have higher fill pressures, some of them have lower fill pressures, but 3000 is what you will find most often. That tube is were the air for each shot comes from, there can many different ways for getting the pellet inside the barrel, but what you see most often is bolt action PCPs, they even have multi-shot, and even semi-auto airgun because there is no pumping needed between shots! For example the FX (FX stands for "Fredrick Axor, the guy who designed them) airgun company based in Sweden has a two full-blown semi-autos, the Revolution, and the Monsoon. So there is no pumping between shots, and they also happen to be the most powerful kind of air gun the Airforce Condor made right here is the good ole' U.S. of A is one of the most powerful small bore airguns, or if you look at the big bore airguns, all of them are PCPs, because that is the most effient way to do it. Dennis Quackenbush makes some serious airguns, I would check him out if I were you! Also they have NO recoil, and they are not hold senitive, so you can shoot them almost any ways you want to, they are the most similar to fire arms. OK, now for the down sides, they tend to be more expensive, the European PCPs cost as much as three months rent for some people. but there are affordable options! like the Benjamin Discovery (I am doing a full review of it later) which only cost about $400 WITH a pump!!! that is the other issue that some people find themselves facing, how to fill their PCP, you have three main option, a hand pump, like what comes with the Discovery, a scuba tank that needs to be filled at a dive shop, of an electric compressor(they cost upwards of $2000, so usually only airgun clubs buy them...). I think that the benefits out weight the negative in so many ways, that I don't mind the physical labor of a hand pump(that and I am too cheap to keep having to pay for some one to fill a scuba tank for me). Oh, and I feel like I should tell you all the olympic air guns, both rifles, and pistols, are PCP!
CO2 is a second favorite of mine, offering several benefits of a PCP, they can easily be multi-shot, they have no recoil, they can't be as powerful though because CO2's highest pressure at normal tempatures is only 900 psi. Also you must pay for CO2 "powerlets" or you can do what called "bulk fill" which is where you have a refillable tank attached to the gun, the powerlets are not reusable. A few examples of nice CO2 guns are the Crosman 2250, the NightStalker, and the Crosman 1077. but as you can see they are all lower powered, another example which might just be one of the very best CO2 guns in my opinion, is the Hammerli 850 Magnum! Also there are a million other CO2 powered BB pistols, if that is what you are looking for might I suggest looking at the Crosman C11.
Next up is single-stroke, and multi-pump Pneumatic, I groups these together, because the powerplant is the same, the only difference is how many times you need to pump, and as a side note, what dictates the number of pumps is what velocity you are looking for and how efficient the pump is, and how effectively the airgun uses the air. This kind of air gun is what most kids start with, they are usually the cheapest, and have very decent accuracy. They are a wonderful first choice if you are new to Airguns, they also have very nice, less cheaply made multi-pumps like the Benjamin Sheridan blue streak. A lot of lower entry level competion gun are multi pump or single stroke, look at the Avanti 853C Legend EX,or one of my favorite, the IZH-46 pistol. this is a good powerplant to start with if you don't want to shell out a lot of money. To see how it works click here.
Finally spring powered rifles, the most common by far, they are powered by a compressed spring that pushes on a piston. So when you pull the trigger the piston slams forward and compresses the air in the chamber which in turn pushes the pellet down the barrel. this is completely self contained, and they can be very accurate, the TX200 is a world class spring gun that can be found at almost every Field target competition nation wide! Spring guns tend to be very hold sensitive, and they are limited in power, and they tend to have very harsh firing characteristics, if you get into airguns with this powerplant with out knowing certain things, then it can be very discouraging. So if you choose this as your first gun, just be prepared for trial and error, and possibly some frustration. One excellent starter spring gun is the IZH-61, it is accurate and easy to use, plus, I think it looks cool, but that is an acquired taste. To see how a spring gun works click here.
Please feel free to leave questions and comments.
Next up will be a review of the Benjamin Discovery duel fuel rifle!