After tinners advice when my sumatra power locked last year i bought a predator hammer spring. After reassembly the gun was down on power but i knew how the adjust it to get the power up as it was only 9ftlb in the chrono but could not be arsed to stip it again so just used it for garden plinking fun. Gun had been working ok up until i last used it 3mths ago. Today pulled it out to use and the bugger is not firing again. Feels like it is power locked again. But why though as the pressure om rifle guage is on 190 bar which is fine. The hammer spring is not that old either. Plenty of heft in the spring as the gun is heavy to cock compared to the standard spring. Is this a common fault on the 707/sumartra rifles? At a loss what has caused this to happen again.