I have been assembling my M4 together these days and it is shooting at a very low fps.
First I tested my gun with a method I came up with on the internet, but I don't know if it is a reliable way to show that whether my gun has an airleak problem or not so please take a look!
And if this is the case, is it because of my air nozzle or tappet plate? (Hop up had been reinstalled several times and should not be the main problem)
Thanks for the help！