Cyma Platinum SLR AK 105 hop up issue

[scrumpy]

With no hop up applied I'm getting about 315fps, but as soon as I apply even the smallest amount of hop the FPS plummets to the 150's. Is this normal or would it be worth swapping out the hop rubber for something softer?

 

[strykerles]

Always a good idea to swap out the hop rubber from standard. Clean out your inner barrel too

 

[The_Lord_Poncho]

Yes, this isnt normal. That kind of reduction should only happen if you are cranking the hop enough to lift depleted uranium BBs. Assuming you don:t have deep enough pockets to feed that habit, it would seem that either the bucking is torn/nub incorrectly fitted, or something else weird is going on with the hop bucking combo. Either way, the way forward is swapping to a good quality bucking and nub combo - and crucially a combination that is known to play well with your particular hop unit and gearbox/nozzle length (or if there is a paucity of Info on this, be prepared for some trial and error).