I took my HPC .25 out today to site in a changed scope. I noticed that my POI was quite a bit lower than I expected. So I put the chrony on it and to my surprise it was going at 685 FPS where it had been going at 860! No air leaking that I could tell, but I’ll let it sit. I then upped the regulator pressure from 130 to 150 bar and the FPS went to 714. I moved the hammer spring between 3.5 and 4 with no effect. Since this is my first and only FX, I’m at a loss as to what caused the drop. It’s been rock solid up to now. Is there an o-ring that may have gone out that I need to look for? The gun is clearly quieter now than normal. Any help is appreciated.
FX Panthers Hunter Compact FPS Drop
- Thread starter Pfddi
- Start date
What was the pressure on bottle?
Is pressure in the bottle above regulated pressure?
Is pressure in the bottle above regulated pressure?
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The regulator on my Panthera Compact Hunter .25 Cal is at 140 bar.
The micro adjustment is at 2.8 and it shoots perfectly.
The micro adjustment is at 2.8 and it shoots perfectly.
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I went back and forth on both the reg pressure and the hammer spring tension. I could not get the FPS over 714 no matter what I did. I was shooting 25.39g JTS pellets.
I just went and fired it with no pellet in it. I put my hand over the breech and when I shoot it, I can feel the pressure on my hand so I must have blown a breech o-ring I'm guessing. Is there one in the breech? I'm pretty confident I shouldn't feel any pressure on my hand at all when the gun is fired!
I just went and fired it with no pellet in it. I put my hand over the breech and when I shoot it, I can feel the pressure on my hand so I must have blown a breech o-ring I'm guessing. Is there one in the breech? I'm pretty confident I shouldn't feel any pressure on my hand at all when the gun is fired!
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There’s an o’ring at the beginning of the barrel…. But loosing it should not imply so many difference in fps.
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Yes, I believe there should be a breech o-ring, and if it is gone it may well explain your drop in muzzle velocity.
Don't have anything specific to the Hunter Compact, but the barrel exploded view for the regular Panthera is here:
https://fxairguns.com/wp-content/uploads/2023/03/F10636-Panthera-pipshroud-sprangskiss.pdf
Don't have anything specific to the Hunter Compact, but the barrel exploded view for the regular Panthera is here:
https://fxairguns.com/wp-content/uploads/2023/03/F10636-Panthera-pipshroud-sprangskiss.pdf
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Thanks @TMH - I found the view but now I have another problem that I had when I got the gun. One of the M4-10 screws (15) came stripped when I got the gun new, so I have never been able to take the barrel off. I guess I'll have to figure out how to remove it and then replace it. I may try and take it to a machine shop and see if they can't get it out for me. I don't have the tools to do that. Here's the problem screw. Then maybe I can get it apart to change the o-ring.
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