FX Impact not reaching Maximum Velocity

[broekzwans]

have you considered enlarging the transfer port? if you make it slightly oval (in the direction of the barrel) more air will be able to pass the TP and go into the barrel so there is some potential there. Too large has no added effects but you'll find the break-even point while enlarging and measuring.

 

[Umer118]

That I can do, I can also increase the regulated air volume, but my point is that why isn't my stock impact performing as every one else's 

Almost everyone crosses the 900 fps mark even at 120 bar pressure with the delrin mod. I cant even go above 870 at 150 bars reg 

 

[BigTinBoat]

That I can do, I can also increase the regulated air volume, but my point is that why isn't my stock impact performing as every one else's 

Almost everyone crosses the 900 fps mark even at 120 bar pressure with the delrin mod. I cant even go above 870 at 150 bars reg

Replace the delrin you put in with a STOCK O-ring and see what happens. This appears (to me) to be the difference in your gun and a "stock" gun

 

[AirSupply]

It sounds to me like some sort of air restriction. Have you had the gun apart?

 

[AirSupply]

If you’ve had the valve housing out check it went back in correctly aligned. The big grub screw that holds it in place will usually square the housing up as you tighten it but if it’s on an angle and the grub screw tightens against the edge the port at the top will be partly covered. This will restrict airflow and could be your issue. 

 

[Umer118]

Will replace that delrin, but before that delrin, te velocity didnt exceed 840 FPS

 

[Umer118]

If you’ve had the valve housing out check it went back in correctly aligned. The big grub screw that holds it in place will usually square the housing up as you tighten it but if it’s on an angle and the grub screw tightens against the edge the port at the top will be partly covered. This will restrict airflow and could be your issue. 

That has been checked, and yes i did take the gun apart, all is aligned. the only thing i can think of is that probably my valve spring is longer or stiffer or something.

 

[AirSupply]

Checked here. 44.4 to 44.7mm

 

[Umer118]

Checked here. 44.4 to 44.7mm

Yup , all good here

 

[Umer118]

Is there a possibility that the valve spring is stiff longer something? Because it's the only thing I can think of.... the movement is smooth n all

 

[tomhu0918]

My impact X .25 700mm. Still can not reach 850fps.(Only 770~810fps)

I did everything I could. 



So I ordered HUMA regulator. Waiting for it coming now. Hoping it will increase the velocity.

 

[Umer118]

I wanted that too but currently it is out of stock

 

[sniperlabyo]

My impact X .25 700mm. Still can not reach 850fps.(Only 770~810fps)

I did everything I could. 



So I ordered HUMA regulator. Waiting for it coming now. Hoping it will increase the velocity.

If you have150b reg pressure output , your problem is some where else to get 900fps+ with 33.9g not the reg assembly!



Most likely it’s the fallowing:

1. C4 the valve rod has 3 parts the screw on to it C1, B26, and B28 any one of them gets loose it will make the rod longer and reduce the FPS. With valve stop removed the C1 will stick out from the action about 4mm when every part is bottom out and tight. If unable to screw on those parts tight the thread maybe strip, be careful not to use reg pressure above 150b the rod threads are not designed or tested for reliablety and not covered by warranty.

2. C3 bumper if totally smash the fps will brop you need to increase hsta or reg pressure to get the speed back up. Best to replace C3

3. B12, feederpin guide where B10 feeder pin holder where B8 feeder pin is mounted not properly aligned with rear block. AirSupply covered this measurement. 

4. B19 reloading rod/bar is unscrewing from A10 reloading block. This will affect TP alignment. B19 is lock tighted to prevent this from happening.

 

[13brv3]

With valve stop removed the C1 will stick out from the action about 4mm when every part is bottom out and tight.

There was a popular, and often quoted Impact troubleshooting guide that's been out for years, and it shows 6.0-6.5 mm sticking out. Has that changed over the years? I've struggled with lower than advertised power, and my C1 rod sticks out about 6.5mm If that should be 4mm, then I probably ought to take it apart and check. 

Thanks,

Rusty

 

[Glem.Chally]

My impact X .25 700mm. Still can not reach 850fps.(Only 770~810fps)

I did everything I could. 



So I ordered HUMA regulator. Waiting for it coming now. Hoping it will increase the velocity.

If you have150b reg pressure output , your problem is some where else to get 900fps+ with 33.9g not the reg assembly!



Most likely it’s the fallowing:

1. C4 the valve rod has 3 parts the screw on to it C1, B26, and B28 any one of them gets loose it will make the rod longer and reduce the FPS. With valve stop removed the C1 will stick out from the action about 4mm when every part is bottom out and tight. If unable to screw on those parts tight the thread maybe strip, be careful not to use reg pressure above 150b the rod threads are not designed or tested for reliablety and not covered by warranty.

2. C3 bumper if totally smash the fps will brop you need to increase hsta or reg pressure to get the speed back up. Best to replace C3

3. B12, feederpin guide where B10 feeder pin holder where B8 feeder pin is mounted not properly aligned with rear block. AirSupply covered this measurement. 

4. B19 reloading rod/bar is unscrewing from A10 reloading block. This will affect TP alignment. B19 is lock tighted to prevent this from happening.

I just want to say thanks for taking the time to give such accurate and pointed technical advice on the forum. Much appreciated Ernest.

 

[tomhu0918]

Mr Ernest,



I finally reach the velocity over 920fps easily. Yes, it is not the regulator issue. 

I just disassembly the impact as following video. I only follow the procedure to 7:25". Tight every components and back assembly .

I even don't know which parts is loose. Any way, it works! Appreciated!

https://www.youtube.com/watch?v=TjLeO7O8DA0



But I met new problem.

My hammer spring lost tension. So the hammer wheel was out of function. I don't the know the reason.

Could you please let me know how to fix it?

Thank you.

https://youtu.be/BAitxpxcLtg

 

[sniperlabyo]

Apply rear pressure to slide bar while turning the power wheel, slide bar should move forward??

 

[tomhu0918]

Mr Ernest,



Thanks for your response!

I just reassembly the parts again. The wheel looks like get normal.

Would you please help to check it is OK again?





https://youtu.be/BaQfDngoUbw

 

[sniperlabyo]

Looks fine— when the wheel at min you have more play on slide bar, constantly push slide bar to the wheel not away, when you rotate the wheel CW or CCW the slide bar will move. Why you think it not working?? 



Remove wheel and look at the back of the wheel there is a off centered cam, a pin adjustment screw thats in the slide bar makes contact with the cam, the hight of the cam is set on high.

Note: no spring tention while the gun is uncock so the slide bar will move slightly depending on the preload of the spring

 

[13brv3]

I just disassembly the impact as following video. I only follow the procedure to 7:25". Tight every components and back assembly .

I even don't know which parts is loose. Any way, it works! Appreciated!

Did you happen to notice the distance the hammerseat extends from the front of the housing with the valve adjuster removed? I'm still trying to determine if that should be 6-6.5mm or 4mm as Ernest mentioned.

Thanks,

Rusty