FX Impact not reaching Maximum Velocity

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Umer118

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Apr 3, 2016
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Punjab
I'm sorry if this topic has been discussed but I've searched this forum completely. 

My impact .22 is not reaching its maximum velocity. I have checked everything. At all setting at the max I have reached a maximum of 880 fps with JSB 18s, reg at 150bar, valve opened fully and by fully I mean completely taking off the adjuster. I have also added the delrin washer between the hammer seat and the hammer instead of o ring. Even then this is the maximum velocity. 

Every things to my knowledge has been checked at factory specks, all orings are fine, no leak, guage has been checked. 6mm valve , the probe is in line with the barrel hole etc

When I checked the velocity, with the hammer adjuster screw also tightened with no play on max I got 850fps and on low power I got 890 fps. So I thought I have over tightened the fine tuner screw . Now with the wheel on MAX there is a 1mm play in the black fine tuner . I get 890 and when I lower the wheel to minimum I get 880, so there is no major difference with the power wheel 

I cannot send the gun to any dealer as there is no dealer support etc here. Also I have a little experience of tuning pcps so I'm sure I can do what's required by myself 

Please Help 
 
I experienced the same problem you're encountering. Based on advice received on this forum, I have been able to get excellent velocity with my Impact X .22 caliber.

1) Leave the valve control knob either off or completely extended.

2) Turn the regulator pressure to 100-110 bar.

3) Turn the power wheel to minimum.

4) Now with your chronograph, test the velocity of your preferred pellet weight.

5) Gradually increase the reg pressure and the power wheel (slowly, in increments).

6) Once you reach a plateau in velocity, you can fine tune the velocity -- to preserve air -- by adjusting the valve control knob.

This worked wonders for me with my Impact. 

Try it. Be patient.
 
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Hitting things harder is not the prefered method to make things go faster:) Its a balance of forces, and 2manyAirGunz has provided a really good basic tuning guide, I highly recommend that you try it once you have a fully standard gun/sorted the current issue. A fully standard .22 Impact (500mm barrel) should be running at around 910 fps at 115bar with the hammer spring adjusted to about 18mm. These are guidelines not hard rules

Replacing the bumper with a Delrin sleave is also not a good idea as the Delrin will expand with every hammer strike. The expanded sleeve will then impede the valve rod as it moves forward into the fine tune knob housing. This effectively shortens the overall length of travel and reduces the maximum velocity. The nbr90 o ring is a consumable,it prevents jarring the valve nipple and potentially unlocking it from the stem, it also softens the recoil from hammer strike. There should be no reason to do this even for a .30 cal, having a heavier hammer would be better in that case.

Have you verified that your gauges are accurate? Those standard gauges are just the pitts, in my humble opinion it's like chasing your own tail.

Remove your bottle and de pressurise the gun. Then from the rear using an Allen key try to move the valve forwards. How smooth is this movement, does the rod glide or does it move in a jerking fashion?

How fast do you want to actually to run, and what pellet?
 
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I've done all of this , but cant go up, at 110 bar my velocity is around 840 fps. Keep in mind I have changed the hammer seat oring with a delrin which normally increases the fps alot but not mine 

~~~~~~~~

Sorry I could not help.

Check out this video by Earnest Rowe. It may give you some clue as to your problem:

https://www.youtube.com/watch?v=kJqAw9T80QY
Click to expand...


 
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Thank you Riazp and 2manyAirgunz 

I'll try it once more and update, as far as the guages are concerned, the regulator guage shows 10 bar less , have checked it with the main gugae and the main guage is tested with the bauer guage on my compressor and the fill station guage. As the main guage comes to 150 the reg guage is at 140 n then both decrease pressure simultaneously. 

I believe I have done all of this but I'll do it systematically once again n see 


 
Upvote 0
I'm sorry if this topic has been discussed but I've searched this forum completely. 

My impact .22 is not reaching its maximum velocity. I have checked everything. At all setting at the max I have reached a maximum of 880 fps with JSB 18s, reg at 150bar, valve opened fully and by fully I mean completely taking off the adjuster. I have also added the delrin washer between the hammer seat and the hammer instead of o ring. Even then this is the maximum velocity. 

Every things to my knowledge has been checked at factory specks, all orings are fine, no leak, guage has been checked. 6mm valve , the probe is in line with the barrel hole etc

When I checked the velocity, with the hammer adjuster screw also tightened with no play on max I got 850fps and on low power I got 890 fps. So I thought I have over tightened the fine tuner screw . Now with the wheel on MAX there is a 1mm play in the black fine tuner . I get 890 and when I lower the wheel to minimum I get 880, so there is no major difference with the power wheel 

I cannot send the gun to any dealer as there is no dealer support etc here. Also I have a little experience of tuning pcps so I'm sure I can do what's required by myself 

Please Help
Click to expand...

How exactly did you test for leaks? 
 
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One thing to also consider is the hammer adjustment screw. I believe you said you had it screws in until there is no longer any play. I would back it off a fair amount. Then fire a round over the chronograph. Note where the velocity is at. screw the adjustment screw in one revolution, fire another round,rinse and repeat. You should see the velocity start to increase. At some point, the velocity will plateau. Going past that point isn’t going to do a whole lot except render the power wheel inop. Meaning there really isn’t going to be much difference between the min and max setting if at all. I’d probably put reg pressure on about 120 ish and then make the adjustments I just spoke of. Recognize though that typically the gauges are pretty inaccurate on the Impacts. This is just my suggestion though from experience in shooting my own Impact.
 
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