[holim]

So yeah, recently I have bought a Proto SLG 09. First of all I was happy with this product but later a problem accured.
Without air it's "clicking" like it should be but with air it shoots only after 3rd or 4th trigger pull. The bolt is lubed, 10BMP and Millenium mode is set on.

Any ideas how it could be fixed?

[The Inflicted]

This problem happens because the battery doesn't have enough juice to make the solenoid kick the sear hard enough to make it let go of the bolt.
You can usually solve this problem by:

1. Replacing the battery
2. Removing the sear spring and compressing it slightly to make it a little weaker
3. Raising the dwell value (if your board allows this)

What kind of battery are you using and how new is it?

[holim]

I am using unorigianl battery(cheap one). Proto battery is discharged

[The Inflicted]

Try using a brand-new Energizer or Duracell alkaline and see if it improves things.
Dry-cell "Heavy duty" batteries often don't work in the SLG, even when fresh.

[holim]

Will do. Thanks