Im currently trying to be build a sniper airgun installed with a qev it is my first time and im new into all this and i hope u guys can help me expand my knowledge and enlighten me on my problems.
1st off a slight example of my goal. Here is the picture:

I did not make this gun and i do not take any credit for anything of it.
Ok i have just started building my gun and im working on the QEV i have got a few questions i have actually tried talking to the person who made the gun he helped me the first day in giving me a tutorial post but its in french and when i translate it to English i can barely understand it. I have tried getting back to the creator of the gun but he doesn't want to reply me.
Here is the link to the tutorial:
This 1 is in french.
http://patator.frbb.net/conseils-aides- ... light=tuto
This 1 is in english.
http://babelfish.yahoo.com/translate_ur ... =Translate
My Questions:
1st question and most important question is how is this thing suppose to work? if someone could explain it to me i would really appreciate it!
2nd question also very important how am i suppose to measure and what to measure? (referring to stage 1 of the guide)
3rd question what should i use for the piston?
4th question how long should the spring be?
5th question what if i only got parts that are all female parts? like the t joint. i cant find a male-female t joint part. Can I improvise?
This are all my questions i hope someone can help me out! Im like getting desperate haha. If u guys need more information or pictures or anything to make things more clear so u can answer my questions please let me know i will try to provide more information.





