The autococker is one of the most well-know
paintball guns (or
markers) on the market today. It is a
closed-bolt semi-automatic gun that is actually a modified
pump gun. Worr games introduced this gun after the original creators worked out a way to make the old system of fire, which involved two disparate steps (the cocking and the firing) into the modern system of semi auto, where shots can be fired in sequence without an additional cocking step. This basically allows the user to get the 'one trigger pull, one shot' behavior expected from most guns, as well as paintball markers, today.
Unlike other high-end markers such as the Angel, Shocker, Impulse, or Bushmaster, which are electropneumatic, the autococker is all mechanical and pneumatic. This means that no batteries are required to operate this gun, folks. Nevertheless, the rate of fire on an autococker is comparable to the low-end of electropneumatic guns.
Many paintball players will tell you that an autococker is the most complex gun out today. However, that is not entirely the case. At first glance, the autococker does in fact have a large number of moving parts, as well as hoses and pump arms. The error of the term complex, however, is that an autococker functions very similarly to other markers, even electropneumatic ones, except that the majority of the parts are externally visible.
Once the initial awe of all the parts passes, it becomes easy to explain that the parts of an autococker can be broken down into simple systems. The gun itself can be divided into three regions, the first being the front or pneumatic block. This is a piece of aluminum that is milled with air ports, into which is plugged the low pressure regulator. It is so called because the pressure output of this regulator, commonly called the LPR, is in the range of 35-90 psi. This reg has a small hose, called LP hose or just autococker hose at times, at the end, which connects to perhaps the most confusing part. It is called a 3-way (also 4-way) valve. It is so called because it has three hose leads on it for LP hose. The center lead takes the input from the LPR. The other two leads on either side are responsible for dispersing the air to the pneumatic ram, which is nothing more than a piston with hose leads on each end. The function of the 3-way is to recock the gun after a ball has been fired. When the 3-way is in position to put air in the back of the ram, the gun is ready to fire; this is the closed position. After a ball has been fired, the 3-way is switched, and the air goes to the front of the ram, thus pushing it back and recocking the gun.
The ram is connected by a round, long piece of metal threaded on each end, called the pump arm, to the back block. This is another piece of aluminum, only instead of air channels, there are two holes in it. One, the larger hole, is the hole through which the bolt is inserted, and usually secured by a pin that goes across the length of the bolt called the bolt pin. The bottom and smaller hole is the hole through which the cocking rod passes. This rod is what actually connects the back block to the hammer and valve, which is responsible for releasing the air that fires the ball. When the air is in the front of the ram, the back block is pushed backwards, catching the cocking rod and pulling the hammer back until it is held back by the sear. Also, when the back block goes backwards, the bolt is pulled back and the breech is opened, allowing for a paintball to roll out of the feed tube and into the chamber. Shortly after, the air again reaches the back of the ram, and the block goes forward, closing the bolt with the ball in the breech, ready to fire. Since the hammer is now held in place by the sear, the cocking rod stays back. At this point, the gun is ready to shoot again.
The piece that ties the front and back blocks together is called the body. It is the body that receives air from the air source, be it compressed air or carbon dioxide CO2. Some people will tell you that an autococker cannot be used with CO2; this is not true, though it is always the best bet to use compressed air for the sake of consistency and lack of temperature change. The body holds the valve and hammer assembly, which is housed in the lower half of the gun. The upper tube, or bolt tube, houses the bolt and the breech. Below the body, but attached in a central fashion, is the grip frame. This is the device that, aside from performing the obvious task if giving the user a place to hold the gun and pull the trigger, is responsible for making all of the events of firing and recocking occur. In recent times, many different grip frames have come out, but in general, they function by causing two events. The first is releasing the sear. When the sear lowers, the hammer is released, and the force of the mainspring behind it makes it fly forward, striking the valve and releasing a burst of air before the force of the air in the air chamber and the valve spring re-close the valve. This burst of air is what fires the ball out of the breech, passing through a vertical hole into the upper tube, through the face of the bolt, and onto the paintball. Now, the hammer is forward, the ball is gone. The next event, which allows for the semi-automatic behavior, is the recocking. The trigger is connected to the 3-way by a rod called the timing rod. This rod is what allows for the motion of the trigger to open and close (or reposition, your choice of semantics) the 3-way. This, in turn, makes the whole recocking action happen.
This is where timing comes into play. To make the gun fire correctly, what has to occur is the fire event followed closely by the recock event. To achieve this behavior, both the sear release and timing rod are connected to the trigger, though by different techniques. When the user depresses the trigger a certain distance, about half way through the pull by custom, the sear releases. Shortly after, the gun recocks because the trigger and in turn the timing rod have pulled the 3-way into its other state. The way that this is adjusted is by controlling the length of the timing rod and by adjusting the depth of the sear lug. The timing rod has a small threaded bolt on it called the collar. By turning this either way, the length of the timing rod, and therefore the distance required before the gun recocks, can be controlled. Similarly, by adjusting the sear lug, the gun tech can control when the sear releases. By lengthening (dropping) it, the sear has to depress farther before the hammer can slip away. Conversely, a shorter lug means that the fire event will occur sooner in the trigger pull. An in depth timing and tuning howto is beyond the scope of this write-up, but the general rule of timing is set your timing rod so the 3-way doesn't leak, then adjust your lug until the gun fires then immediately recocks. By any means, it is usually a good idea to watch some one retime an autococker before doing it yourself. Most paintball shops will time your gun for you for free or for very little money; if the store you go to doesn't, try the next one.
Autocockers are arguably the most customizable guns, on grounds that every part can be changed for another aftermarket one. The purpose of these parts range from cosmetics to performance. Many vendors sell many parts, and a lot of them probably don't do much, but there are some that do. When considering upgrades for an autococker, there are good resources for determining which are legit and which are hype. www.pbnation.com, for instance, hosts forums in which users have compared experiences with various products. The lesson here is that when selecting parts, one should do copious research, and talk with those who own the part, and make sure that one is familiar with all the details.
Overall, the autococker can be as high-end or low-end as you want it to be. If you choose to spend the money and build your own special cocker, or really spend and buy a high-high-end gun such as a FreeFlow, things can get pricey. On the other hand, an intermediate player can spend $300-450 and be satisfied with their gun, and still have the potential to expand in the future.