Qev Gun Design Help!!

[Ansen]

hi everyone, i need some help improving my air rifle im not a pro at this,
i prefer to seek help before making a mistake
some specs:
shoots 6mm steel ball bearing
900mm long 7mm inside diameter barrel (cant get a smaller one )
im using a 2 position 3 way valve and a Qev as shown in the picture
for now i have a 120 psi compressor (going to upgrade soon )
what changes can i make for improving it ?
what size for the chamber etc... i welcome any change in design
thanks for your help if i made any mistake please do tell me
http://postimg.org/image/vzfmxa8bb/

[matti]

First thing that came to mind was that a 7mm ID barrel with 6mm bb is huge waste of power. 6mm ID barrel would make the biggest difference for sure.
What do you mean you can't get smaller then 7mm pipe ? There are lot of different sources for suitable pipes, where you from ?

Hard to say anything about the chamber because we can't see the length of it from the picture and you didn't give any dimensions for it. You could replace the fill ball valve with inline check valve.

Anyway the basic setup looks fairly good, at least you used QEV and not a ball valve

[Ansen]

Thank you for your reply matti
on second search i got an 8mm OD x 2mm Wall 900mm Long but will the technique on this video work?


i have to order everything online and shipping actually cost me 2 or 3 times the price of the product sometime, it is because im in the middle of the Indian ocean.
the chamber in the picture was just for illustration purposes, i have been using GGDT to fiqure out the volume of the chamber but will 550cm3 be too much?
is the inline check valve same as a non return valve?
last thing, i have no experience with a hammer valve system but will it be more efficient than this setup?
Thanks again!