FX Impact M3 valve adjuster hitting barrel shroud

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Floridaman2005

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Oct 11, 2024
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Hello Nation,

Just purchased a new .22 Impact M3 and was going through all the basics and setting up the rifle. When attempting to adjust the valve adjuster, I noticed that the valve adjuster was hitting the barrel shroud, making it impossible to open passed 3.5 lines. This is my first PCP so I’m still learning everything. What do I need to adjust in order to move the shroud away from the valve adjustment knob?

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My M3 compact .22 does the same thing. But fortunately when the valve knob is backed out and touching the shroud, it is out far enough that it isn’t working. Before you start screwing around with stuff, back yours out until it hits the shroud. Shoot a couple shots over the chronograph. Now turn the knob in a quarter turn. Shoot again and see if your velocity has dropped. If it didn’t then you don’t need to worry about a thing. Fx may install a slightly different valve spring on the compacts to accommodate the tight clearance from the knob to the shroud.
 
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Vetmx said:
My M3 compact .22 does the same thing. But fortunately when the valve knob is backed out and touching the shroud, it is out far enough that it isn’t working. Before you start screwing around with stuff, back yours out until it hits the shroud. Shoot a couple shots over the chronograph. Now turn the knob in a quarter turn. Shoot again and see if your velocity has dropped. If it didn’t then you don’t need to worry about a thing. Fx may install a slightly different valve spring on the compacts to accommodate the tight clearance from the knob to the shroud.
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Great point 👍 I have a chronograph on the way and will get to the bottom of that and try that asap. Thank you!

My only concern would be if it didn’t effect what I was doing now but may still be limiting when I move to heavier ammo and when I turn up the volume.
 
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coastal drifter said:
Might want to call Utah airguns , It just doesnt make sense to me that you cant adjust the vavle adjuster.
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I agree, and it definitely isn’t just mine, there’s a few message board last I’ve found discussing the issue. Nobody really has a fix besides cutting some washers and putting them inside the shroud, but I’m not really a fan of that.
 
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Floridaman2005 said:
How do you remove the shroud? Will this cause any fitment issues?
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The shroud simply unscrews. It is threaded at the end. Your best choice is to probably slightly unscrew the shroud to get the valve adjuster where you want it. Once completely tuned you may find it isn’t an issue and the adjuster will want to be in that far anyway. Maybe not though. If you end up needing it out further than the shroud will allow I personally would unscrew the shroud (not completely just loosened) to the point needed. You could always put a dab of blue loc tite to help secure it in its un tightened state. I would not move the whole barrel assembly forward as I would think that would misalign the transfer port of the barrel.
 
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Trucker3573 said:
The shroud simply unscrews. It is threaded at the end. Your best choice is to probably slightly unscrew the shroud to get the valve adjuster where you want it. Once completely tuned you may find it isn’t an issue and the adjuster will want to be in that far anyway. Maybe not though. If you end up needing it out further than the shroud will allow I personally would unscrew the shroud (not completely just loosened) to the point needed. You could always put a dab of blue loc tite to help secure it in its un tightened state. I would not move the whole barrel assembly forward as I would think that would misalign the transfer port of the barrel.
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Yeah I agree, but I’m not a fan of leaving the shroud loose because that would make things less accurate, or at the very least would make the moderator more susceptible to baffle strikes.
 
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Floridaman2005 said:
Great point 👍 I have a chronograph on the way and will get to the bottom of that and try that asap. Thank you!

My only concern would be if it didn’t effect what I was doing now but may still be limiting when I move to heavier ammo and when I turn up the volume.
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Quite the opposite. When you turn up the volume, your operating range with the valve knob stays pretty much the same because you have more plenum pressure working against it.
 
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It’s not an issue until you test it and determine if it’s an issue. Everyone is jumping the gun here. My knob can hit my shroud on my compact but it doesn’t matter because it’s in the wide open mode when it’s touching. The only thing that could bite you is if who you bought it off of made the gun a compact. If it came from FX that way, you should be fine.
 
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Vetmx said:
It’s not an issue until you test it and determine if it’s an issue. Everyone is jumping the gun here. My knob can hit my shroud on my compact but it doesn’t matter because it’s in the wide open mode when it’s touching. The only thing that could bite you is if who you bought it off of made the gun a compact. If it came from FX that way, you should be fine.
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It’s definitely an issue. On my Impact Compact, I can turn the valve adjuster fully open past the fourth line without it hitting the shroud—there's still a few millimeters of clearance. If your valve adjuster has the standard 4 lines but can only reach the 3th line before touching the shroud, then something’s not right. Even if it doesn’t affect velocity, the adjuster should be able to open fully without obstruction.

The valve adjuster is the magic touch when tuning the impact.
 
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Ries said:
It’s definitely an issue. On my Impact Compact, I can turn the valve adjuster fully open past the fourth line without it hitting the shroud—there's still a few millimeters of clearance. If your valve adjuster has the standard 4 lines but can only reach the 3th line before touching the shroud, then something’s not right. Even if it doesn’t affect velocity, the adjuster should be able to open fully without obstruction.

The valve adjuster is the magic touch when tuning the impact.
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You’re preaching to the choir about the FX Impact. But I didn’t realize he was only at line 3. Mine stops about line 4. And all of my Impacts generally start to work about half way between line 3 and 4. I was reading some of this while in my tree stand. But I would still like to see what his chronograph has to say. All it takes is a different spring in there and you can grow or shrink the adjustment range on that knob.
 
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