Large FX Impact POI Shift Issues (Impact from Hell)

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zachoak

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Sep 19, 2024
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Hello! I'm new to the forum, but this seems like the best place to get advice. I am not new to airguns, but I am new to the FX Impact. I work on all of my guns, centerfire and air, and have never had this many issues. I'm almost ready to throw it in the trash.

I am including all of my problems, even though they might not be related.

Some Backstory:

I bought a Demo FX Impact M3 .22 600MM from Utah Airguns a few months ago and have had nothing but problems with it. It seems that every time I buy an airgun from them there is some major problem with it. I guess I haven't learned my lesson. To start off with, my "functioning gun" came with a junk regulator (4 disks flattened and caused severe reg creep). The I installed a new Huma regulator. It was also missing a few random parts, that have been replaced. I installed a Slug Power Kit and had several issues with power consistency. I have since removed everything, but the hammer weight. I have installed a STX heavy barrel liner and a carbon fiber barrel sleeve. I have lightly glued the ends to keep the sleeve from moving. At some point the valve rod bent (not sure if it was like that when I received it or after, but it has since been straightened out within a few thou. The first stage of the trigger sometimes gets hung up and won't reset. It will fire then proceed to fire when on safe. I have tried adjusting it, but the issue always comes back. There has been a few other problems, but I'm sure you guys don't want to read an entire book.

I currently have about 450 slugs through this liner. I am currently shoots NSA 31.2gr @ 990fps. My tune is 1st reg @250 bar, Second reg @ ~173 bar, front valve adjuster @ .404, macro @14 and micro @ 4.375

Now to my current problem. Every time I take the gun out of its case (after sitting for a day) my zero/point of impact is severely off from the day before. It seems to trend down and to the right about 2" at 40yds (my zero). I have had some extremes as far as 4 inches to the right. I check my velocity every time I take it out, and it stays within 5fps of 990fps. I can refill my bottle and shoot as many rounds as I want, and it will not return to my original zero. When I put the gun away for the day, I lay it down on its side on a foam pad. There is nothing that should be tweaking the barrel. The temperature, and humidity have stayed roughly the same, throughout all of this. I have tried retuning my gun a few times, and it doesn't seem to improve my situation either.

So far I have done the following to try to help remedy the poi shift.
1.) Carbon Fiber Sleeve (I have never tried shooting this with the factory o-rings)
2.) Ensured that everything is torqued to spec (scope base, scope rings, backbone, pic rail, barrel clamp, set screw that attaches holds down the barrel by the transfer port)
3.) Put on a trusted scope that has never had any issues before
4.) Retuned gun and ensured that nothing is getting bumped
5.) Checked weights and lengths of slugs to ensure I wasn't getting weird seating depth issues. Also includes make sure slugs are clearing transfer port.
6.) Swapped to 25cal Donnyfl moderator incase it was clipping
7.) Used gauge pins to ensure slugs aren't slipping shroud
8.) Holding the gun in many different ways (I have heard they can be hold sensitive)
9.) Removed all o-rings touching the outer sleeve of the barrel

Some protentional issues that may be causing it
1.) Carbon fiber sleeve has about .010 of play inside of the out sleeve. (Should it be a light press fit?)
2.) The scope rail does not allow for centered scope rings on the tube. The front ring have about .100 of clearance from the turret. It is currently sitting in the only place for proper eye relief
3.) Possible bad o-ring that I can't find. (I have taken the gun apart several times and can't seem to find any that are bad)
4.) The entire barrel system (related to the carbon fiber sleeve fitment)

I'm sorry for the rambling, but I am at my wits end with this rifle. Has anyone ever had this many issues with POI shift? How were you able to fix them. It would be nice to know why you decided the change the part(s) and how much did it effect the outcome? I'm willing to try just about anything at this point. I don't mind spending money to fix it, but I am also getting really sick of dumping money into it. I haven't contacted Utah airguns about this issue, but I will not be doing that. That's a story for another time. I have debated on putting and Airmarksman backbone on it, even though it doesn't seem to be hold sensitive. I have also considered sleeving the old liner and glueing the carbon fiber sleeve to the outer liner, installing a tensioner, or machining a solid barrel. This is a hunting rifle, so I don't want to add a bunch of weight to an already heavy gun as I walk several miles every time I go out. First shot accuracy is very important to me, and I can't trust this rifle which is a shame as I hadn't heard of anything negative about these guns until I really started researching the issues I've had.

I've attached a picture of my scope mounting so you can see what I am talking about.

Thanks for the help!

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I used to have reg creep on my Impact gen 1. It was set at 150 and most often it was around 170 out of the case. A few empty shots and it was good until sitting overnight. That was the most important reason for me to get rid of it.
I had EDMU installed so numbers were painfully clear. One would think FX has their stuff together by now, but an accurate pressure gauge might take you forward. It could rather easily be sold when not needed anymore.
 
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The valve rod is a tricky one. I had enormous trouble getting it hold air with the power plenum. Also I noticed Gerhard installing his pretty much the wrong way on the tutorial video. He twisted it instead of just assembling it the right way. Can't remember much about it anymore but I'm sure one isn't supposed to have the rod twisted in every direction.
 
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cahil_2 said:
Have you tried a different barrel? Also, have you tried rotating the liner 90 degrees?
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I haven't tried a different barrel yet, but I do have the original pellet liner I can try. I'm testing to see if having the shroud on or off effects anything at the moment. I unfortunately can only test it once a day due to the fact it only happens when the rifle sits overnight. When you say rotating the liner, are you referring to to clocking the barrel?
 
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Will74 said:
The valve rod is a tricky one. I had enormous trouble getting it hold air with the power plenum. Also I noticed Gerhard installing his pretty much the wrong way on the tutorial video. He twisted it instead of just assembling it the right way. Can't remember much about it anymore but I'm sure one isn't supposed to have the rod twisted in every direction.
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I haven't seen the video from Gerhard, but if you have a link to it, I would be interested in watching it. The rod is definitely supposed to be straight. I just happened to notice because it had lost a lot of power. My front valve was also sticking out further than it was supposed (due to the bend). I was running my hammer adjusters to the max so it could have been what caused it. When I took the rifle apart that was the only thing I could find wrong. Only time will tell if it is going to bend again. With the regulator creep you mentioned. The Huma regulator did take care of most of it. Having owned other airguns, I've had to dry fire all of them if they sit overnight. They all creep a few bar. With buying a new gauge, the smaller power changes from sitting over night don't seem to affect it. I can adjust my tune all day long and they all hit in relatively the same spot. In my case something must be moving overnight; I just can't figure out what and why.
 
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I have been down the same M3 road albeit a little less bumpy. The gun has many demons that can emerge as you increase the power. You won’t see those demons on South African YT videos.

In the real world, if you find yourself storing your gun on a foam pad under the bed or dousing it with holy water before taking the first shot of the day, it’s time to quit the sunk cost fallacy, sell it and move on.
 
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173b on the second reg and needing a hammer weight with a 600mm barrel are probably where some of your issues are coming from. Just because a gun will do something doesn’t mean it’s happy doing it. Just because you hear guys claiming greatness running their guns hard doesn’t mean that they aren’t constantly having issues with the side effects. Two things. Read between the lines when getting the information from someone you don’t shoot with daily because of all the half truths in this hobby. And two, by keeping an Impact operating within the parameters of the components it came with, you’ll have a better chance of have a more stable gun. The gun will never be perfect. It can’t be. Its chassis is made of too many parts and so is the barrel. But you should start by not driving it so hard or consider a 700mm barrel.
 
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Vetmx said:
173b on the second reg and needing a hammer weight with a 600mm barrel are probably where some of your issues are coming from. Just because a gun will do something doesn’t mean it’s happy doing it. Just because you hear guys claiming greatness running their guns hard doesn’t mean that they aren’t constantly having issues with the side effects. Two things. Read between the lines when getting the information from someone you don’t shoot with daily because of all the half truths in this hobby. And two, by keeping an Impact operating within the parameters of the components it came with, you’ll have a better chance of have a more stable gun. The gun will never be perfect. It can’t be. Its chassis is made of too many parts and so is the barrel. But you should start by not driving it so hard or consider a 700mm barrel.
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Good advice. My first FX was a Maverick and as I have posted before I should do hard time for what I put that gun through while I learned about tuning, slugs and repair.
Best lesson I learned is you don’t need to push the gun to its outer limits and when you do? Inevitable frustration and an endless barrage of nagging issue will beset you.
FX does themselves no favors having influencers advocate for pushing their upper tier guns well beyond the design parameters. Sure they will do it, sometimes, maybe most of the time but never all of the time. The result is a steady supply of posts like the OP’s stating frustration and disappointment with their FX purchase. Many who have not owned an Impact see these posts and assume it is a general problem with Impacts. While this is not wholly accurate the perception is hard to deny.
We have two M3’s. Both 600mm 22’s. My wife’s gun is set up to shoot 25.39 pellets and the 22 gr Hybrids. Her gun is bone stock and the second reg is right at 140 bar. Mine has a slug liner and a power tune kit installed minus the pin probe. My gun shoots NSA 27.5 @ 975 fps. The only reason it has the slug kit hammer in it is because I ran out of hammer at about 145 bar. While I was tuning these slugs the groups got smaller the faster I drove them. I wanted to see what they would do above 950 fps. They did a better with the reg set 155 bar. I have no desire to drive it any harder because I already know what awaits beyond that power level.
 
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Chukar60 said:
Good advice. My first FX was a Maverick and as I have posted before I should do hard time for what I put that gun through while I learned about tuning, slugs and repair.
Best lesson I learned is you don’t need to push the gun to its outer limits and when you do? Inevitable frustration and an endless barrage of nagging issue will beset you.
FX does themselves no favors having influencers advocate for pushing their upper tier guns well beyond the design parameters. Sure they will do it, sometimes, maybe most of the time but never all of the time. The result is a steady supply of posts like the OP’s stating frustration and disappointment with their FX purchase. Many who have not owned an Impact see these posts and assume it is a general problem with Impacts. While this is not wholly accurate the perception is hard to deny.
We have two M3’s. Both 600mm 22’s. My wife’s gun is set up to shoot 25.39 pellets and the 22 gr Hybrids. Her gun is bone stock and the second reg is right at 140 bar. Mine has a slug liner and a power tune kit installed minus the pin probe. My gun shoots NSA 27.5 @ 975 fps. The only reason it has the slug kit hammer in it is because I ran out of hammer at about 145 bar. While I was tuning these slugs the groups got smaller the faster I drove them. I wanted to see what they would do above 950 fps. They did a better with the reg set 155 bar. I have no desire to drive it any harder because I already know what awaits beyond that power level.
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Yes, and my most wicked, accurate and very consistent .25 slug M3 is set at 153b. Sending slugs at 1,040fps with no hammer weight or “kits”. The gun has some components that help but nothing I would consider hot rod stuff. No issues with the known FX issues with this gun for two years. Once I got it built and tuned, I never touched it again.
 
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The best advise I can give you is sell the gun and take your losses! Don’t take this wrong, but just getting a small amount of your path and frustration? You won’t be happy!
Impacts are a very unique and reliable platform, but not for all, I have worked on hundreds of them! And I still am finding things that don’t work out?
This frustration is common and starts with usually a sub 700 mm barrel and a desire for what I would call big power requiring mods?

None of this is your fault! Who knows who has been in side that gun and done what? Valve, reg, valve rod, hammer, spring and barrel components all can be swapped and miss matched?

If it was mine, i would turn everything down for trouble shooting purposes and start over! 100 bar reg, crony, pellets and start working my way up. At least this way you can start removing suspects? Sorry and good luck👍🏻
 
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