SpudFiles

Barrel is 1.9 cm by 110 cm. Firing Volume is 1.9cm * 25cm. About 75 cm3 as GGDT predicts.
Is 1.9X25cm enough to shoot at 10bar?
And is there any more ergonomical design?
Which trigger valve would be the best option? I heard about slide valves, but I don't know how to translate it. Can you explain how they work, so I look for something similar?

Going to make and test it this weekend. Also will post pictures of 2 my other guns. I finished them at last. So, I would be glad to know about any mistakes, before I go and buy all the stuff.
Thanks in advance.

I'm guessing the red line behind the "firing volume" is a ball valve?

Ok few things wrong with the design. QEVs are not inline as drawn. However, since you plan on shooting on only 10 bars, you can probably get away with a well modified sprinkler valve. Also if you plan on using a QEV then your pilot valve cannot be placed as drawn. However a sprinkler valve can be piloted like that.

Now, GGDT does not predict your chamber size. That is the actual size (approximately). It does, however, predict your muzzle velocity. Use it to determine the size and pressure of your chamber. You can also use the P1V1=P2V2 formula to figure out how big you'll want your filling tank.

This are valves http://www.pneumax.ru/upload/iblock/9e1 ... 7f2ea4.pdf
How about this? And what to use as a pilot-trigger valve? Slide valve? If so how do I attach it?

Nope, I think the first is inline (rare and I've never seen one used on a gun) and the second and third are not. Check out the Pneumatic showcase to see some examples of common uses of QEVs.