ProWin Hopup Chamber for AK Series Airsoft AEG Rifles

"This is the best AK hopup and ive used it in my CYMA builds, it solves the shifting gearbox problem with newer AKs (without 4 bottom receiver screws, non TM) but it doesnt fit LCT aks. It changes the distance of the hopup bucking to the gearbox, and the magazine well feeding tube positioning.
I have builds that have a 1 FPS variance between all shots because of it that can stack BBs on top of each other at long ranges.

"Reason why I bought this: Built a Cyma AKs74u with a Polar star Jack in it. Was having issues with the nozzle staying aligned to the hop-up and barrel.

Outcome: I DID have to file down the top screw on the gearbox where the nozzle is (I knew that going in based on the dimensions of the gearbox and what I saw on the pictures for this item). Once I slowly filed down the gearbox, slowly and patiently checking when the hop-up slid in with very little resistance. I put it all together. And it all lined up perfectly (I did have to add electrical tape shims on the bottom of the gearbox since the nozzle gets pulled down when you tighten the grip screw, hop-up had nothing to do with this).

Over all review: very good hop up. Has good alignment. You may need to file down the feed hole (before the feed stopper) on your mags to have a smoother reload. All parts from the plastic Cyma hop up fit it perfectly.

Side note, the extrusion where the hop up meets the gearbox will not make full contact (be flush) with the gearbox, this is normal

My 74u is happy, I am happy.

"Fit my E&L aks74u with prommy barrel but now I cant screw down the whole front part of the gun LMAO