FX Panthera first shot low FPS

[sparker]

Hello all,

I was discussing this in another thread but it seems like my issue must be slightly different. I have a Panthera .22 Compact and the first shot is always 40-80fps slow after sitting for an hour or more. The regulator the gun came with had 5-8 bar reg creep which made the issue worse. Even after 600+ pellets it wouldn't settle in so I swapped in the reg from my Maverick which I know is good. The issue still persists after 3-4 different attempts at fixing the regulator. I have tried at 110 bar and 120 bar reg settings. Here are my shot strings:

840
880
870
---
844
878
890
---
809
879
880
---
838
880
892
---
845
884
892

For a little extra background, Utah Airguns said they tuned it for me and when I shot my first few shots I just thought they did a crappy tune. The more pellets I put through it in a sitting the better it shoots. After 3-4 mags it's pretty tight FPS but when it sits it goes to poop again. Could it be a faulty valve? Utah Airguns and FX support both think it's the regulator but I've already swapped that out.

I'd like to avoid sending it in if I can.

 

[Airgunmann]

Probably oring sticktion on the valve stem it plagues any gun with a balance valve

 

[nervoustrig]

Assuming the Panthera has a valve rod similar to the Impact, you’re probably seeing O-ring stiction.

Tuning - FX Impact Mk2/M3 - slower first shot - no reg creep - quasi-scientific analysis

Hi guys, Welcome everybody. This is my first post here. I have a problem with my Impact Mk2 PP .30. The reg pressure is 145 bars. When I shoot shot after shot then my v0 is 260m/s. However, when the gun sits for a couple of hours then the first shot is 250m/s despite the exact same reg...

www.airgunnation.com

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[Airgunmann]

Does the reg still creep after you swapped it out ?

 

[Airgunmann]

It's got a stem on either side of the valve and there is a oring in the front valve cap to seal the stem I just had to change one for a friend his blue out the only orings I had that would fit was a viton oring hopefully it helps move easier

 

[Airgunmann]

The hammer doesn't ride on the valve stem like the impacts and there isn't a pinch spot for the oring like on the impact

 

[darknes]

most problems are in the regulator. check it if the landing surface on the bottom is well polished as are the springs. it also depends on which version of the regulator you have, if it is still made of plastic or brass, or the latest version is brass with a piece of plastic in it, see photo.


I had a piece of that plastic just like a hair and it was causing me problems.

and as another thing in low pressure setting it does it more often than at higher pressure it stops doing it for me when I set 150 bar at 145 bar it rises only slightly.

 

[sparker]

Does the reg still creep after you swapped it out ?

no

 

[sparker]

Probably oring sticktion on the valve stem it plagues any gun with a balance valve

Is there a way to improve that without disassembly? Maybe some oil in the fill port and a couple hundred more pellets?

 

[Airgunmann]

If the reg doesn't creep it isn't the reg try turning it up higher and some more hammer to it for a quick burst of high pressure air and 25 gr pellets or heavier maybe haven't heard of to many complaints about a slow first shot but a lot of people are running higher reg pressures for slugs though also

 

[ACard]

Have a 22 Panthera 700. Exact same issue. Life has kept me busy enough that I have not had a chance to tinker with it as of yet.

 

[sparker]

Just put a couple drops of super lube in it and went through a tin of 200. Actually seems like it is getting worse. Going from 850 to 800 fps now just between shots without sitting. It used to "warm up" and run fine after the first mag.

Guess I tear it down or send it in.

 

[Airgunmann]

To get at the front oring you need to degas the whole gun pull the plenum which is really tight I used a soft jaw vise and a strap wrench then a pair of snap ring pliers to get the valve retainer out. Watch Ernest rowes disassemble video it's very helpful I would also try a viton oring but I don't know how long they will last I guess I'll find out soon enough

 

[Airgunmann]

I'll run the gun over the Chrono it's been sitting a few days since I changed to a viton oring

 

[JimD]

Totally different gun but my P35-25 did this when the hammer spring was set too low for the regulator setting. When I moved the hammer spring setting up more in line with the regulator the issue totally went away. If you haven't tried increasing the hammer spring to the point the velocity stops rising and then trying slight adjustments around that point for best accuracy you may want to try it.

 

[sparker]

Totally different gun but my P35-25 did this when the hammer spring was set too low for the regulator setting. When I moved the hammer spring setting up more in line with the regulator the issue totally went away. If you haven't tried increasing the hammer spring to the point the velocity stops rising and then trying slight adjustments around that point for best accuracy you may want to try it.

I’ve tried so many variations, this isn’t a tune problem but thanks.

 

[sparker]

Well, it seems the oil in the fill probe made its way to the valve overnight. Now first shot is 890+fps but it's still having excessive fps swings of +-12ish.

 

[Emu]

After filling my Panthera, first shot is always lower.

So, no much trouble.

 

[sparker]

After fill, fine whatever. After sitting for an hour, for a hunting gun, not acceptable.

 

[Emu]

After fill, fine whatever. After sitting for an hour, for a hunting gun, not acceptable.

Agree!