I send many of my videos of modification/ improvements of fx impact to Frederick directly.
Bhaur
Bhaur
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Tuning $$$$$$$$$$$ HEY FX $$$$$$$$$
- Thread starter 2D1C
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Not quite true. I have a bunch of FX guns and I have absolutely no complaints.
I suspect they ARE listening - to the thousands and thousands of satisfied people who buy their guns…
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I have no issues to address. Maybe - because I am taking well care of my guns, I said maybe or because I am just lucky?
I have never wasted my time sending back to a dealer since day one. There is nothing on the airgun you cannot fix in an hour, between two beers and a coffee.................
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My problem is my innate ability to take things apart, put them back together and somehow end up with extra parts.........lol
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I don’t even have that much innate ability to take things apart and put them back together. I just don’t have many problems at all. If I take it apart it’s because I want to do something new!
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As stated, a cold gun string will come later. I took about 2 turn on the string then backed it down using the valve to get this string 
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I wrote that in the original thread created by me but I will write it here again: shooting a shot or two to be on track is just a workaround. It shouldn't be needed in the gun with Impact's price. There are guns which cost a fraction of that price and they don't suffer from that problem. The valve in Impact is it's advantage and disadvantage at the same time. The following approach fixed my issue with the first shot:
- peek washer to make the tolerances tighter,
- FKM80 (Viton) oring instead of PUR90 (the best one would be the one with PTFE coating but it's hard to find it),
- polished valve rod,
- a healthy dosage of Huma low viscosivity lube.
All the details can be found here:
https://www.airgunnation.com/topic/fx-impact-mk2-slower-first-shot-no-reg-creep/
mubhaur has a more elegant solution requiring more machining work though.
P.S. It does not matter if there is an original reg installed or a Huma one - if you install a digital gauge to check your reg pressure and it is within 2 bars of difference from the readout which you made 24hrs before then you are just fine. Your first shot cannot be 30FPS lower because of that. It may be 4-6FPS lower.
- peek washer to make the tolerances tighter,
- FKM80 (Viton) oring instead of PUR90 (the best one would be the one with PTFE coating but it's hard to find it),
- polished valve rod,
- a healthy dosage of Huma low viscosivity lube.
All the details can be found here:
https://www.airgunnation.com/topic/fx-impact-mk2-slower-first-shot-no-reg-creep/
mubhaur has a more elegant solution requiring more machining work though.
P.S. It does not matter if there is an original reg installed or a Huma one - if you install a digital gauge to check your reg pressure and it is within 2 bars of difference from the readout which you made 24hrs before then you are just fine. Your first shot cannot be 30FPS lower because of that. It may be 4-6FPS lower.
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I need first shot accuracy for hunting- it's the only shot that matters. Would you mind sharing a few guns that do not have the issue the Impact does? Is anyone you know going to make up some washers to sell?
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Every gun in my safe has spot on first shot FPS. Including a lowly regulated Prod. With simple guns, and as long as your poppet isn’t made of modeling clay, no reg creep or very little with the perfect hammer spring setting equals a happy hunter. I made extra peek washers when I made them for my Impacts but gave them to a friend on the forum. They are tiny little things to make.
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Virtually any regulated PCP with a simple knock-open valve will have a dependable first shot provided:
- the hammer spring tension is adjusted to the velocity knee, and
- the regulator's valve seat is in decent shape
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It's when you get into more sophisticated balanced valves with O-rings that stiction and limited self-regulation characteristics tend to complicate things.
So in the world of small caliber PCPs (.177, .22, and .25 cal), the list of guns capable of a reliable cold shot is much longer than the list of those that aren't.
By the way, the regulator need not be anything fancy or expensive. Even generic $20 paintball paintball regulators usually perform perfectly well if you take a few minutes to smooth the seat. Longevity is another matter but that is a variable shared with many OEM regulators.
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My RAW HM1000X .22 and .25 that are highly modified with a kind of balanced valve and an O ring on the valve rod are as good for the first shot as these were without balanced valve.
FX Impact is a more complicated design. A lot of parts to work in harmony.
As you know I have made the front part of the M3 plenum on the design of mk1, the issue of extrusion etc. has been resolved. The 1st shot after even many days is very near to the set fps hence no issue to the hunter. For target shooting I understand that even the stock design can also be fine as in target shooting we can shoot a few pellets before the start of the game.
Again to overcome the issue I understand that keeping the higher hammer hit and restricting the valve travel from valve adjuster also helps.
The extra hit of hammer overcomes the stickiness issue of O ring and the restricted valve travel doesn't allow the fps to increase.
Umair Bhaur
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I have the m3 and the new vulcan 3 700mm barrel , vulcan wins absolutely getting an moa at 130 yards with nsa 31.2 slugs .22 , it even has more air capacity
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Virtually any regulated PCP with no reg creep and no oring under pressure on the valve stem. There might be issues with valve poppet stiction if it is conical. This can be resolved with a peek valve poppet. I found that a peek valve poppet is not a must in Impact. At least it is not needed to fix the first shot issue.
Guys, if you are interested in peek washers then I can prepare them for you and ship worldwide. Just drop me a PM. I will wait a couple of days to collect the orders.
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Here are the results cold gun. I don't know why I lost velocity over all?? However by adding more spring as suggested did make a big difference. Thanks to all for helping!
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Looking good!
BTW, don't be concerned with the difference in the average velocity compared to 2 days ago. At least not unless it continues to migrate downward. As it is, it represents a mere 1.3% difference which can easily be explained by a difference in lighting.
Additionally, shot #2 at 880fps is a major outlier that drags down the average.
BTW, don't be concerned with the difference in the average velocity compared to 2 days ago. At least not unless it continues to migrate downward. As it is, it represents a mere 1.3% difference which can easily be explained by a difference in lighting.
Additionally, shot #2 at 880fps is a major outlier that drags down the average.
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