Huben Huben GK1 Double Tap Issues

Hi There,

I am experiencing an odd issue with the GK1, or at least I think it is odd, not sure maybe its working as intended. First thing I noticed after the pistol arrived was the tank was filled, this was odd as the other airguns I own were shipped empty. The second thing I noticed was the rattle from the trigger. None of the reviews ever mentioned this but the screw that holds the trigger and connects the trigger to the action is large enough that there is a few milimeters of play and this obviously rattles back and fourth. The trigger is also extremely loose and has a slight rattle due to the play as well (no amount of adjustment could make it tight without also preventing the gun from firing at all). I did get the trigger to a passable state, basically making it as heavy as possible while still firing, but now I am running into a more 'gamebreaking' issue.

The gun is semi-auto but if fired as fast as I can pull the trigger, it kind of just farts out the second pellet. On the chronograph its a over a 50% drop in velocity if I double tap, if I space out the shots as if I was charging the gun manually between shots it works fine.

Can any other GK1 owners confirm if they have any of the same issues with theirs? Mine is the V3 .25 FAC, I followed Gregors video to unlock power adjustment and modify the trigger pull weights, no other modifications were made, but I am using the DonnyFL ryu suppresor as there was supposedly and issue with getting the huben ones and they offered me the RYU as a substitute.
 
First, you need to understand the principle that the GK1 operates under. Then you need to follow the instructions that came with it. One of which is clearly stated that you are NOT to do rapid fire as you have. The reason you have less velocity on a rapid second shot is the size of the bleed slot on the closing valve pintle. It take a little time to recharge the air chamber. Go to Gregor's K1 explanation of its function to fully understand this.

I cannot speak about your trigger slop, because your explanation makes no sense to me. but I suggest that perhaps you have now misadjusted your trigger to resolve an issue outside the scope of the adjustments. Please review Gregor's explanations before proceeding further with your adjustments.
 
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First, you need to understand the principle that the GK1 operates under. Then you need to follow the instructions that came with it. One of which is clearly stated that you are NOT to do rapid fire as you have. The reason you have less velocity on a rapid second shot is the size of the bleed slot on the closing valve pintle. It take a little time to recharge the air chamber. Go to Gregor's K1 explanation of its function to fully understand this.

I cannot speak about your trigger slop, because your explanation makes no sense to me. but I suggest that perhaps you have now misadjusted your trigger to resolve an issue outside the scope of the adjustments. Please review Gregor's explanations before proceeding further with your adjustments.
Not sure what does not make sense about a loose trigger or rattling, if yours does not rattle than it would be a defect. The term rapid fire is not defined, pulling the trigger as soon as it resets to me is not rapid fire but rather semi-automatic fire. I have other semi-auto pcp's that do not have this issue, and the hatsan blitzt which is a true rapid fire and does not have this issue. Why would an unregulated pcp need to recharge? Can you post a link to Gregors comments on this?
 
Not sure what does not make sense about a loose trigger or rattling, if yours does not rattle than it would be a defect. The term rapid fire is not defined, pulling the trigger as soon as it resets to me is not rapid fire but rather semi-automatic fire. I have other semi-auto pcp's that do not have this issue, and the hatsan blitzt which is a true rapid fire and does not have this issue. Why would an unregulated pcp need to recharge? Can you post a link to Gregors comments on this?
Mine shoots doubles very quickly. I put two into a raccoon head two cm apart, implying no loss of velocity. Have also done that on targets. The potential issue comes from dumping a lot of shots rapidly. That would be adiabatic cooling from the air expansion which could freeze any moisture in the action or barrel if many shots are fired in rapid succession.

I would advise you to return it. You shouldn’t have to deal with what seems to be several separate issues with a new pistol.