assembly. I removed the cap, radiused the tube edge, and replaced the o-ring. That, and the very basic high power setup of the valve were the only issues..it's a well made piece.
After many hours of tuning,including a whole new valve and lightened striker, I have mine producing 30 shots between 900 and 930 fps using .20 benjamin pellets (14.3 grains?)I think its time to tune it down a bit, to the 870 fps range.