Gas powered airsoft handguns have been around for many years. They have gradually evolved from simple fixed slide pistols to advanced blow back guns capable of semi and full auto firing. The way these gas guns work is never simple. In fact, gas guns are way more complicated than their electric counterparts:

In the world of AEG you have several standards (which were built around the Marui architecture) to follow. In the world of gas guns, however, standard is almost entirely absent. Different manufacturers have different patented designs, that’s why guns from Western Arms are never compatible with guns from Marui.

AEG allows you to manipulate the mechbox in many creative ways, but gas gun doesn’t have such flexibility. In fact, as a beginner, your options are severely limited.

There is no fixed equation on gas gun upgrade and maintenance. You will need to build up your expertise on this subject matter bit by bit. This book teaches you the basics – it tells you what is doable and what should NEVER be done so that all sorts of costly and stupid mistakes can be avoided.

This book also demonstrates the kind of upgrade that is appropriate for IPSC practical shooting. The motto of IPSC is DVC (Diligentia, Vis, Celeritas), which means accuracy, power and speed. You have to hit the target accurately and without delay. While power is relatively limited, speed (how fast you shoot) isn't. Airsoft shooting takes place from rather close ranges, and shooters are racing against the clock. The focus of upgrade is therefore not on power, but on trigger response and recoil action (too much blowback is no good). We will show you a step-by-step upgrade of the Marui Hi-Capa for practical shooting.

Below shows the book TOC:

INTRODUCTION
GETTING READY
Tools you’re going to need
Tools you don’t absolutely need
Handling of screws
The proper ways of taking things apart and putting them back together
GAS GUN ARCHITECTURE
The anatomy of a gas handgun
Possible points of failure
Possible upgrades and performance optimization tricks
UPGRADE & MAINTENANCE Q & A
FPS increase in meter readings VS performance increase in a practical sense: the law of diminishing marginal gain in performance.
What are the differences between 134a, Green Gas and Red Gas?
How about CO2?
Proper gas charging and handling techniques
Double Action VS Single Action
Can you turn a GBB into a fixed slide NBB?
0.20g BBs versus 0.25g BBs versus 0.30g BBs: the heavier the better?
Does FPS always go hand in hand with Joule?
What is the difference between the FPS system and the Joule system?
How do you use FPS to measure Joule?
How do you use FPS to give an estimate of the range?
What is wrong with the soda can test?
What is right with the soda can test?
What is the most accurate way to measure FPS?
Can you show me how to use a basic speed tester?
What are the key elements of a high accuracy setup?
How to improve accuracy with short barrel?
Can a long barrel deliver higher accuracy and range?
What is good about a high precision barrel?
How to maximize the effectiveness of a high precision barrel?
What is the drawback of using a high precision barrel?
What can cause the hopup rubber to break?
I have to wind my hop almost all the way up just to get flat flight. What is wrong?
Why is fixed hopup not desirable?
What are the legal restrictions?
How to seek repair service if I don’t want to do it myself?
Is it good to get into the business of selling gas pistols?
Why do we see so many cheap clones around?
What is the issue on trade dressing?
What kind of changes had the China-made airsoft guns brought to the market?
So is it easy to set up my own brand of airsoft products?
How is a gas powered airsoft gun different from a RAM (Real Action Marker)? Is conversion between the two architectures possible?
HI-CAPA UPGRADE FOR PRACTICAL SHOOTING