G36 FPS drops massively with hop-up turned up

[FMJ]

Hey, I recently put together a G36 (TM but with some other parts thrown in). The box works great and I have a consistant 330ish FPS with hop-up turned off and .2's. The problem is as soon as you turn the hop-up up at all FPS drop rapidly. I know FPS is effected by hop-up as it's basically a restriction but I am talking a drop down to 210fps when half way on! Right down below 200 with it near full. In the past I have only found hop-up to add or subtract about 10fps.

Any ideas? The cylinder has a good seal as does the piston. Hop-up is assembled correct and tight. The nozzle appears to go forward as far as is can but it's hard to tell how well it meshes with the hop-up due to it resetting a few mm back from it. I don't understand how turning a bit of hop-up on is dropping FPS so much!

Also on the G36 hop-up what is the function of the little spring loaded latch in the hop-up unit the the nozzle acts over? Is it to prevent bb's falling backwards? Seems as bit pointless as the gun works fine with or without it?

[FMJ]

Re: G36 FPS drops massively with hop-up turned up

So I tried shaving down the front of the tappet plate for a more positive seal. All that seems to have done is cause a new issue whereby every 5 to 10 semi auto shots the trigger locks and has to be flipped to auto to clear... FFS I remember why I stopped airsofting ten years ago now. So much frustration with kit.