[Drakker]

1) This is normal. The harder the valve is hit, the more gas is released, the more randomness it adds to the equation (cool down, speed of the gas expansion, etc). It is not impossible to make a consistent high FPS setup, but it takes experience. Keep working at it.

2) Sometimes all that's needed is a bit of lube. But more likely you should make sure your BBU is assembled correctly. On some pistols it could be related to the hammer assembly pushing up too hard/too high, though I've personally never had this problem with any of my Hi-capas/1911s. Sometimes it happens because the recoil spring is too weak. It could also be caused by a too tight combination of slide/rails. This can be fixed in many ways, but it would involve polishing the rails and slide to remove excess material, and I don't want you to get any ideas here. This is tricky and I would not recommend you do it on your first build without supervision. But it's unlikely to be the problem, since it worked before. Check what you changed lately and start there.