Although this article focuses on improvements to my QB/XS 7 co2 gun, the information would most likely transfer directly to most or the basic co2 rifles. The QB 78 is a good gun out of the box and the one I currently own and use. I have only made three alterations to my QB since new:
1) I tuned the trigger, which is an easy job for anyone who can handle a screw driver and needs no additional parts to make a huge improvement. Further improvement could be gained by adding some shims either side of the trigger to stop the slop, which is fairly noticeable though I have not as yet bothered with this. The feel of the trigger is now smooth and sure whereas before it was distinctly jerky making it hard to judge when the gun was going to fire.
2) I improved the stock by adding some height to the comb to make the gun more comfortable and improve my accuracy, especially using telescopic sights. This was a more complex job though easy enough for anyone with some basic woodworking skills and access to a table saw or otherwise more skilled at hand sawing than myself!
3) I added an adjustable butt plate/pad. This was an easy job with some filing of the new butt plate to do and simply screw it all together in what ever position suits the shooter.
These measures have greatly improved its performance and feel.
Advantages and disadvantages of co2 guns over other types of air weapon
One of the biggest advantages of co2 airguns is their relatively low cost compared to comparable springers and more so, pre charged pcp guns. Co2 guns will give you the recoil free action of a pcp which is a great advantage over spring guns in terms of accuracy especially for the less experienced air gunner. They are also often reasonably easy to tune as in the case of the QB
Wanting a cheap but powerful and accurate gun for hunting and never really mastering marksmanship with a springer is what attracted me to these guns in the first place. I had been using an ASI Magnum spring powered gun which was a great gun for the money though I had been used to using a Sharp Innova pump up pneumatic beforehand and found this much easier to hit the mark with. I was however fed up with pumping it up every shot and since the UK gun laws had changed making co2 guns legal, I decided to give one a go.
The disadvantages I have found are that there is a considerable power drop once the powerlet begins to empty. I have found that I get approximately 80 – 90 shots from a powerlet yet only the first 50-60 are consistent. With the QB it is necessary to shoot off the excess co2 before changing powerlets. This can be done without loading pellets into the gun but is laborious. Unscrewing the tube cap before the powerlets are empty (the QB takes 2 powerlets at a time) can cause damage to the seals. Co2 guns are also subject to a loss of power as temperature drops. This is most noticeable below 5 degrees C.
In conclusion, co2 power has a great advantage over spring power guns in terms of recoil and therefore can be more accurate. There are good out of the box guns around that are excellent with minimal work. The power drop as the powerlets empty can make recharging them laborious and they are adversely effected by cold weather, however as an entry level gun they have some great advantages as well as being great fun!