I would be inclined to say that your issues are not with the parts, it is with the adjustment and tuning of those parts. Frankly, the parts you have in the rifle right now are just fine, you just need to spend more time tuning it. It also wouldn't hurt to downgrade that spring a little, or use a hop system better suited to insanely high fps than our own bump-in-a-rubber-sleeve system.
Granted, 520 is not insanely high, but I find that the bump-system maxes out at a little over 400. After that, the bb needs more stabilization in order that it does not wobble in flight.
Granted, 520 is not insanely high, but I find that the bump-system maxes out at a little over 400. After that, the bb needs more stabilization in order that it does not wobble in flight.