Riddle Me This, Riddle Me That…

Forums PCP Airguns Riddle Me This, Riddle Me That…

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    Greenarrow
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    230 bar fill

    130 bar regulator setting (? Whatever factory setting is)

    1. 845 fps

    2. 855 

    3. 870

    4. 890

    5. 890

    6. 890

    7. 890

    8. 890

     

    Stop.  Reload magazine.  Fire.  The shot string will start low then velocity climbs and levels off after 4-5 shots.  When on a fresh fill (230 bar) the max velocity will generally be higher (910 fps) and seems to drop the max velocity down to the 890 fps range over the majority of the rest of the fill. It does this consistently.  

     

    What do you think is causing this?  

     

    Need more info?  I’ll try to provide it if I can.  

     

    I don’t have a known cause.  I know what I think it is but I want to see what others come up with that have waaaaay more experience at pcp tuning/troubleshooting than I do.  

     

    Any insight is much appreciated.  Thank you!

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    Kaeokini
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    What type / manufacturer of gun? What manufacturer is the regulator?

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    Lewis
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    Sounds like a creeping reg. After some time passes the reg pressure creeps up to a level that the hammer has more trouble opening the valve. To confirm:

    Fill to full pressure and fire one round every 2 minutes or more if they are all at or near your lower figure (850's in your case) = Bingo reg creep.

    Shoot quickly (after the first few shots) or fill only to a level just above your reg setting and the problem goes away. Some regs will settle in after a while others will need to be repaired or replaced.

     

    • This reply was modified 5 months ago by Lewis.
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    Greenarrow
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    That is exactly what I had been thinking.  Thank you Lewis!

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    Peskadot671
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    FX Wildcat .25cal?  8 round clip. Hmmm 

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    Greenarrow
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    FX/FX

    .177

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    intenseaty22
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    I’m no expert on FX guns but have read many folk talk about the dreaded reg creep. I think the fix is a Huma reg. Best confirm that with the resident FX gurus here though. 

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    Greenarrow
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    Yeah, that’s what I was afraid of.  

    I wonder if the creep issue is that way because of the design of the regulator OR is it something else that’s overlooked when assembled?  

     

    I’ll start with looking at the regulator and doing a little tuning and a reseal on it.  O-rings and time are cheap compared to a new regulator.  I’ll contact FX also and see what they can do for me.  Maybe I’ll give them a chance to make it right first.  We’ll see.  I’m a little impatient and may just dig into it myself.  

     

    I have owned 3 FX guns, all regulated. This could be/is the first one I have had a creep issue with.  I have had the Royale 400 .22, Streamline .22 and now this Wildcat .177.  

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    Greenarrow
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    I took the gun down, removed the regulator and did a clean up on it.  I lightly sanded the mating surfaces of the spring washers.  Relubed and reinstalled.  Problem/symptoms no longer exist.  Yay!  I did extensive shooting over the chrony and working with the HST.  It’s dialed in right around 890 fps with an ES of 15.  The tightest ES was a little hotter than I wanted at 930 fps and an average ES 7-8 fps.   I can live with 15ps on average.  That’s shooting JSB 8.4 grain pellets.  Now that it’s consistent, I’ll run through the different pellets to see if anything else shoots tighter.  I’m loving me some Wildcat BP right now!  😸😸😸

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    Saltlake58
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    I talked to the FX tech about my Impact creeping just a bit.  (really nice people and they really do talk to us shooters!)  Their recommendation for Reg Creep is an extra Belville Washer if you've got one.  that applies more pressure to the sealing surfaces.  I did that to mine and didn't completely fix the problem but sure improved it.

    I do the light sanding.  Been considering it for a while, but am a coward and didn't know if it would help or ruin the surfaces.  What type of sand paper did you use and grit did you go to?  Many thanks!

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    Greenarrow
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    Saltlake58

    I talked to the FX tech about my Impact creeping just a bit.  (really nice people and they really do talk to us shooters!)  Their recommendation for Reg Creep is an extra Belville Washer if you've got one.  that applies more pressure to the sealing surfaces.  I did that to mine and didn't completely fix the problem but sure improved it.

    I do the light sanding.  Been considering it for a while, but am a coward and didn't know if it would help or ruin the surfaces.  What type of sand paper did you use and grit did you go to?  Many thanks!

    I used a small piece of 600 wet/dry on the table top.  My spring washers are black so when I sanded the mating surfaces (where they contact the other spring washers when stacked) the sanded area showed silver/bright.  I used just enough pressure with my index finger to keep contact with the washer while I did a circular sanding motion.  I didn’t count but it was maybe 15-20 circles per surface area.  It was easy to see progress since the color changed on the sanded areas.  The flats weren’t large by any means, just enough to take the sharp edge off and create a small flat for the washers to stack together better.  

    I don’t know exactly made the difference but I’m not experiencing the same thing now as I was before the tear down.  I did have to use heat and a vise to separate (unscrew aluminum and brass) the regulator to remove the piston.  If you just want to sand the washers and not get into the rest of it, you don’t need to do that.  Unscrewing the nut will allow you to remove the washers.  

    If you do sand your washers, I’m pretty sure the measurement you made BEFORE actually removing the nut and sanding them, will be a ballpark reference to where the set point was from the factory.  I guesstimated where to set mine AFTER sanding.  I know I lowered my pressure because I intentionally backed the nut out 1/8 of a turn from the before measurement.  My max velocity before taking the gun apart was 1090 fps.  Max velocity after reassembly was 930 fps.  I backed the HST out to get velocity in the 890 fps range. 

    After reassembling the rifle I shot some over the chrony to see where it was.  Then I cranked the HST all the way in and made a mark at 12 o’clock on the brass adjuster for reference.  I would shoot 1 magazine worth (8 shots) then dial the HST out 1 full turn after each mag shot.  I saw maximum velocity (and tightest ES) at 4 turns out.  I arrived at the 890 fps mark at 6 turns out from maximum HST.  I noticed the report was less at that point and accuracy was still right on so I left it there.  Below is a picture of my chicken scratch notes I took while doing all this.  

    I watched this to give me an idea what to expect when I got to tinkering with the regulator.  HTH

     

     

     

    • This reply was modified 5 months ago by Greenarrow.
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