Well, I've got 2 one in decent nick and one wreck for spares, and they both have the same fault!!! Its just a deeply rubbish design and build (stock screws much too high as well resulting in stock splits). Cobham in his book on air ruifle maintainance mentions the same issue too. No wonder milbro went under, the design is awful. If you work out a way to stablise the trigger unit and make the gun usable please post your findings!