this is Gamos weak side. Great guns for there price but that trigger, ohh that trigger really stinks. I tried tightening the adjustment screw on my 220 when I first got it, all it does is shorten the "first stage", the stock trigger spring is way too stiff for a short crisp release. I wanted a trigger that was fully adjustible and practical, I happen to go with these inserts made by Rich in Mich.
Not to start a debate but from personal experience, they work great on my shadow and hunter 220. Rich is a goog guy and a pleasure to work with. Luckily for us there are ample amount of tuners willing to help. Whomever's insert you decide I'm sure will make that stock trigger ahelluva lot better than what it is now. HTH