Fx Panthera barrel leak, valve seat?

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Powerage

Powerage

Member
Jan 25, 2020
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10
Norway, Norway
Okay so after the weekends shooting I discovered today the Panthera was without pressure . After filling I can hear a hiss through the barrel. I’m suspecting the valve not closing properly. Tried to dry fire a few shots didn’t solve the problem . did anyone else have this problem ? Is there any videos out on how to disassemble the Panthera correctly?
 
Looks like I found the reason . The valvepin is bent. Not sure why this happened. Now I have to get a replacement.

25A4E791-0196-40DE-9ED7-8284E0495EED.jpeg
 
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Just a heads up that others have reported the same issue:

Panthera slow leak

Anyone else been having the slow leak issue? I resealed the gauge block with new orings, and also replaced the x rings in the gauge port of both gauges. Still loses about 20 to 30 bar per night. So it’s not my first guess, maybe it’s the new valve system? Maybe FX will chime in here since I’m...
www.airgunnation.com www.airgunnation.com
 
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There is a rumored issue with the block BEHIND the valve stem where it travels not being bored out enough to receive the valve stem without it hitting the block. FX has been mum on this so far. Perhaps some got sold before they identified and fixed this issue. In any case it should be a warranty job. I’d send it in since just replacing the valve stem fixes the symptom not the actual problem.
 
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Sure looks like classic column buckling yield failure of the small diameter section, causing misalignment of the larger diameter bushing diameter section on the left end. I'm assuming the hammer impacts that left end. Either some overly heavy hammer impact, or possibly dry firing with too little air pressure in the plenum, or maybe the stem needs a different metal with higher yield stress? In case of overtavel of valve with insufficient air pressure, if the right hand end (return spring end) hits a hard stop, there could be big compressive shock forces in that small section.

I'm not completely familiar with this design, just generalizing. Would be interesting to learn the fix. It's a new design, sometimes stresses and failures don't follow what was imagined/chosen in the stress analysis during the design & prototype stage. Or, material supplied didn't have the specified yield strength and got substituted.

Feinwerk
 
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Thanks for the replies . The gun isn’t dryfired without air . I know the consequences of doing that from my dreamline ..

Sending the Panthera back … the dealer is far away and it would take months to get it back I’m afraid .

The first weeks I had the Panthera set to shoot the 30 grain javelins at 1000 fps . Reg 150 macro 20 and micro 3.2 . It gave some nice groups . This weekend I decided to tune the gun for some. 36 gr zan. Reg 165 and hammer almost at max and things started to look nice. After shooting the third mag I heard the air leaching through the barrel

I didn’t find any good videos on how to disassemble the Panthera . I don’t know why no of the YouTube experts has done it yet. After a quick look at the fx schematic document it’s was pretty easy to remove the barrel and access the valve rod . Looks like the valve itself has to come out on the others side. But I don’t know if it’s necessary. Maybe to inspect if anything else is broken.

No tungsten hammer installed
 
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GA_LeadHead said:
I'm hoping FX-USA chimes in here. Just ordered a Panthera last week. This has me concerned.
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Same, I'm reluctant to go shooting now. I've got one of the first batch and it's holding air fine.

Would like to address the issue before I possibly cause any damage. Fingers crossed it's a part replacement fix and I won't have to ship mine out.
 
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Any updates on what exactly is/was wrong with the Panthera valve stem?

Mine is alright currently but there are quite a few in the hands of friends that have recently had bent valve stems and are on their way for repair.
My gun's rail support did have a shallow, almost unfinished looking recess machined for the valve stem with a dimple in the middle making it even shallower.
Changed it out for the huma bottle adapter.

I've haven't had mine in 22 shooting above about 65fpe but still, I find myself half expecting to find an empty gun every time I open the box at the rate they seem to be failing. The Patriot tech I messaged said he is seeing about 80% of the early batch guns coming back... Didn't get any detail in the reply regarding what exactly the cause was but will ask again.
If it's something with the early valve stems themselves I may just preempt the issue and request a replacement part rather than have my gun crap out at some inopportune time.
 
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Feinwerk said:
@Centercut , we were typing at the same time....yep, if there's insufficient clearance for the complete valve travel, it's a mechanical 'crash', very interesting.
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I'm not sure where my .25 Panthera 600mm was leaking, but its fixed. It was a slow leak, and I just couldn't find it without dunking it in the bathtub, and I didn't want to do that. So, I disassembled the gun and cleaned grooves and replaced all the o-rings. The valve stem was NOT bent, and I have been shooting at 87 FPE since I got the gun. It now holds pressure overnight, so I don't know what was leaking but I couldn't spend any more time dicking around trying to find the leak...
I have the 8mm hammer weight but didn't install it since my gun shoots at 87 FPE stock and gets about 20 shots from a 250-bar fill with 135 bar reg pressure. I'm shooting the .25 Altaros Smooth BT 49.5 grain at about 890 fps.

FYI, I shot it side by side with my .25 Impact 700mm with Superior Slug liner and at 50 and 100 yards, the 37 grain ZAN at 990 fps and the 41 grain ZAN at 960 shot extremely well. Once I got it out to 165 yards and over, the 41 grain were superior to the 37 grain, but both were inferior to the 49.5 grain Altaros.
 
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Good news.
FX made a new valverod. Thicker in the middle. I got a new one yesterday and didn't even notice the difference at first.
I wanted to have a few made from stronger and thicker material. But now I will test these for a few thousand rounds and see how it will hold.

Be sure to polish that puppy slightly before installation ;)

2023-04-08 10_17_40-Untitled - Rhinoceros 7 Commercial - [Top].png
 

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Macros said:
Awesome.
Do you have the exact part number?
They've just recently started selling valve pins over on Europe Airguns but the picture is a stock image of the older one, so I've held off for now in case.
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It's the x1-6. If u want to order one, just use my picture with the new and the old one on it. They can measure the thickness.

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