Hi!
I have animated simple action where finger pull the trigger.
When i “start” game and push mouse left button nothing happens!
If you have any idea why this happens, please tell me 
The action is only 3 frames long. Running at 60 frames per second, the action will only last 0.05 seconds. It might actually be working and you just don’t notice it because it’s so short.
Otherwise, I can’t really help you more without a .blend file.
Yeah! Thanks!