Is This What Is Meant By "Regulator Creep?"

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Jim81

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Nov 2, 2017
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Wa, United States
.25 Wildcat Mk2. The gun has been sitting for a few days and just before I head out to the dairy farms I take a couple of bench shots at 50. The first 3 shots are all over the place. From the 4th shot on its hole in hole as long as I am that good. It hits where the crosshairs are when the trigger strikes the hammer.

OK! NO problem! I'll just pop off 3 shots before I get to where the birds are. Then I thought, I wonder how long it takes for it to need the 3 shot 'reaccurizing' process. Well It took me about and hour and a half to return home and I shot from the bench to see if it had 'creeped' if that's what it is. Yup! Shot just like it had been sitting overnight. After 3 shots it was spot on.

I have read folks damming the FX regulators and some jusy install a HUMA before they even shoot the gun. If what I described is regulator 'creep' then I am in the market for a HUMA and my Ipad video showing how to replace it. There are no air leaks evident sitting for weeks with a full 230 bar.

Thanks!
 
Yep, seems like your Wildcat might have it. 

You didn't post any reg pressure numbers, and that is something that would need to be measured to verify creep, but in any event, the reg would ideally not creep at all, or very little. My Impact will occasionally show a 4-5 bar uptick overnight, but typically only with extreme temperature changes. Otherwise solid. Having a first shot after an extended period of time be "off" is not unusual, though, and may not necessarily be due to regulator creep but many other factors.
 
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Damn, another problem with these. I am glad I did not buy a pcp right off like I wanted. I have been doing some research and seems as though every one I “ think I want” has issues. I decide to look at some thing else more reliable, damn if it doesn’t have issues to. The wildcat MK II, took the place of the crown the crown took the place of the impact. It’s mind boggling that you guys just “ over look” these issues as normal. If I spend this much money on an air rifle and it creeps, leaks, cracks, bolts back out etc. I am going to be one pissed off person. Do you guys really find all this, “ normal” ? Because, if so maybe iam not one to own one of these, as bad as I want one, I just don’t know. 

Op, how old is your wild cat MK II ? Does any one know, are they still using that same regulator in the currant guns ? 
 
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Sounds like it's probably creep but if you have a chronograph, check the velocity over the first 5 shots and that will tell you for sure.

If you haven't yet adjusted the hammer spring tension for ~97% of peak velocity, do that and re-check before replacing the regulator. When adjusted in this manner, a slight pressure variation will not influence the velocity (just as an unregulated PCP will hold a tight extreme spread over a broad pressure range).

The other option is to dress the valve seat with wet/dry paper to remove any microscopic scratches. That is the reason the pressure continues to rise slowly over a period of time. Air is weeping through tiny imperfections until the pressure rises high enough to squeeze the seat tight enough to totally halt the migration of air from the high pressure side to the low pressure side. 
 
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The thing that has me wondering if you might have a different issue is that you said "after three shots" accuracy was spot on, while a long-term reg creep issue would normally only affect the first shot. Maybe Wildcat owners will chime in and have other theories as to what may be affecting your rifle. Unfortunately, with no separate regulator pressure gauge, it is not as easy to diagnose a leaky regulator.
 
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If you are willing to invest a little time and a little money, pull the stock and a 'standard' gauge will screw right into the port on the left side of the action. There is brass plug there on mine. Its a port to the regulated chamber. You can see the reg pressure and any changes over time. There are posts here showing where folks have milled out the stock so they can leave the 'reg gauge' all the time. I would at least test it to see any changes but lots of folks swap out WC FX regs for Huma regs. My .22 MKII has a Huma reg, my (3rd before I got a good one) .177 MKI WC still has the FX reg, so some are ok.
 
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ghoststalker if you wait for the perfect PCP you'll be waiting after many of us have shot thousands of rounds. I bought and sold an Impact within 2 months. Too many bells and whistles to go wrong or need to adjust before it's dependable. When I got it the rifle fired when on 'Safe".. I've had about 5 different FXs and 4 other brands. They all had some issues. I have settled now with the WC2. I have thousands of rounds through it and it's extremely accurate. I have done nothing other than clean it twice. Took it out of the box and started shooting. The other keeper I have is a Taipan Veteran Shorty. It's probably more trouble free than the WC2. or will be, it's darn accurate but when I shoot the two side by side the FX is always a slight bit more accurate. I hope my final purchase will be the Dreamline with carbon fiber bottle. Fairly proven design with just the right amount of adjustabilty ans the bottle on the end ensures I won't have to take along spare air with me.

The WC2 is about 1.5 years old. A better gauge of it's dependability is how many rounds have been through it. My WAG it's pretty close to 2000 shots. Bet there are other WC2 owners who have had theirs longer but maybe only 500 shots through it.

To answer some questions asked by the above problem solvers I went and shot 8 rounds through the Caldwell chrono. The 7th shot didn't read but here's the resultsl

1-742 2.-813 3-833 4-840 5-846 6-850 7 XXX 8-841 The third shot and those thereafter could be covered with a fat nickel...at 50 yds. So!! Is that regulator creep or is it something else. I would lean towards a HUMA if it's the regulator as the FX regulator is going to go TU somewhere down the road...way before the HUMA

Thanks to all!!
 
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The hammer spring could be binding, the valve return spring could be binding. The valve stem might be getting caught up, so could the hammer. You may be experiencing hammer bounce. Is it clipping the shroud/silencer? Is the scope holding zero? Are your mounts a quality make? Any sort of pellet sorting? Many other things I left out.
 
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Just as a general term, creep implies a slow leak of high pressure from your HP air supply tank or bottle through the regulator and into the plenum, resulting in an abnormally high plenum pressure. So once you fire a first round after the rifle has been sitting for awhile, the regulated pressure in the plenum should be normal (either factory set or as-adjusted if a variable regulator). A severely leaking regulator would give you erratic results on every shot, to some extent, since pressure would vary constantly depending on the time interval between shots. One might think then that the first shot at abnormally high plenum pressure would be higher in velocity, but if the valve is not able to open sufficiently due to that high plenum pressure, it can end up having lower than normal velocity, as occurred here in your 8-shot test. So there is a self-balancing effect of reg pressure versus valve opening force that can somewhat level the velocity as in unregulated guns.

Bottom line, without monitoring the reg pressure over time, it would be taking a guess to say that the problem is your regulator creeping-- it may not be. Troubleshooting something like this remotely can be hit or miss, even if a lot of people chime in and say they had the same problem. If you did decide to replace your reg, you would probably still want a way to measure the plenum pressure (even though some adjustable HUMA regs have approximate pressure markings on them), so purchasing a pressure gauge for that auxiliary port might not be a bad idea. My two cents...




 
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How difficult are these things to work on, replace the regulator with a HUMA ? Checking for these things that could be binding ? Are there any schematics of the guns, to see what working on one might involve ? It looks like no matter what one you buy, it’s going to need “ fixed” at some point, and I would rather do it myself if at all possible. 
 
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Jim, your string with the gradually increasing velocity over shots 1-4 strongly suggests it is the regulator creeping up over time. I'd say 95% confidence.

The only other defect I have encountered with that sort of idle time dependency was a binding valve stem. It would develop a bit of stiction after sitting idle for a while, and the hammer could not knock it open as well on the first shot. Initially I thought it was regulator creep but after it tested good, I went looking elsewhere and found the binding problem. Replaced it and the gun was rock solid after that.
 
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How difficult are these things to work on, replace the regulator with a HUMA ? Checking for these things that could be binding ? Are there any schematics of the guns, to see what working on one might involve ? It looks like no matter what one you buy, it’s going to need “ fixed” at some point, and I would rather do it myself if at all possible.
Click to expand...

How difficult to work on? I'd say easier than working on your car or any other vehicle. Being competent at airgun repairs probably lends itself to those who are a bit meticulous and pay attention to details. Someone willing to inspect every part and make sure they are clean and free of debris. That "feel" parts together rather than just force them, and don't work in a hurry. I've nicked an o-ring (or two!), but it was always because I wasn't paying attention to alignment, didn't fully re-lube the o-ring, or didn't fix any burrs or rough spots first.

If you are considering an FX rifle, and want to self-maintain it, watching a few of Ernest Rowe's videos on YouTube or elsewhere will give you a good idea of what's involved. There are also exploded parts diagrams on fxairguns.com/support.
 
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1567671219_3397254785d70c3b3a4c9c2.25870952_1B3CD02C-45EC-4219-89A1-E897FEB32E60.jpeg


Anytime a Huma reg needs to get installed in a WC, the bat light comes out. YouTube vids are a good source for knowledge based tutorials, supposedly from experts, provided ALL PERTINENT INFORMATION IS PROVIDED in both disassembly and reassembly, which they are not, and could get someone in trouble screaming for HELP in total frustration. As an example- in one video that has no talking but music playing, it says to use two 4mm steel pins to remove the end cap at the rear of the air tube to access and remove the factory reg. Well, don’t go and waste time sourcing two 4mm pins because the WC MK2 uses 3mm pins. Another- one must make sure and address the AMP reg adjustment grub screw that’s used to adjust reg pressure, in order for the factory reg to be removed. One more- that little bugger sized black ball- make sure and attend to that cause that is easily lost if your not paying attention, because no one in a video addressed its removal prior to pulling the air tube out.Those are just 3 examples of what’s NOT talked about in any videos I’ve seen, and those are the “easy”, non critical items. Most disassembly videos are of the MK1’s, and there’s enough of a difference to cause a first timer some frustration.

The guy in the Bat light is your go-to when it comes to everything and anything Wildcats. Hopefully he chimes in.



Jason, good call on the valve stem possibly sticking. 
 
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It is very simple to install a Huma regulator and by doing so you will benefit by eliminating regulator creep, increased efficiency leading to higher shot count, and rock solid reliability. I recently installed a Huma reg in a friends' new .25 Wildcat MKII for him, and set it up to shoot the JSB 25.4 grain pellets at the factory specification of 47 ft lbs energy... which yielded 110 shots. Then he changed his mind and asked me to set it up to shoot the 33.95 Heavy's, so I reset the reg and hammer spring tension to shoot those pellets at the avg. V of 950 ft/s which is 68 ft lb energy.

So you can see from this example how much more versatile the best air rifle ever invented can be when re-powered with a new Huma engine! Sort of like putting a 427 Hemi in a Ford PInto! VaVooom!

All the best, Chuck
 
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It does sound like you have reg. creep. I do want to point out that although the Huma's are very good regs, they are not perfect, and have issues and problems just like any other reg. IMHO they are better than the stock FX regs, but I bought one a few years ago for my .30 FX Bobcat that developed creep shortly after I installed it. The good side to the story is I emailed Huma (Huub) and I thought he was going to send me a rebuild kit but instead sent an entire new reg. It has been in my Bobcat ever since. As far a ""reg.-ability", its better than the FX reg. that was in the Bobcat which had developed severe creep. But, it is not as good as the stock Cricket reg. I have in my .22 Mini Carbine. How do I know this? Well, I had a Huma in my mini, and the ES over about a two mag string (14 shots per mag) was usually coming in between 9 and 12. Which is very good. But under the exact same conditions in the exact same gun with the exact same tin of JSB 18.1 pellets, I get about half the ES with the Cricket reg. that I get with the Huma reg. I've also had to rebuild some of the Huma regs I've had that developed issues after thousands of rounds. Truth in lending, I've had and installed well in excess of ten of the Huma regs over the past three years...
 
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Post script to the info I shared above about achieving a fairly high shot count with a friends' new Wildcat...this was with a new Wildcat MKII Standard with the 700 mm barrel, which gave me a lot of free velocity which allowed me to keep the reg setting very low…thereby yielding such a high shot count. After 110 shots it actually "fell off the reg" at an incredible 85 Bar showing on the air gauge on the rifle!

Always the best, Chuck
 
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It is very simple to install a Huma regulator and by doing so you will benefit by eliminating regulator creep, increased efficiency leading to higher shot count, and rock solid reliability. I recently installed a Huma reg in a friends' new .25 Wildcat MKII for him, and set it up to shoot the JSB 25.4 grain pellets at the factory specification of 47 ft lbs energy... which yielded 110 shots. Then he changed his mind and asked me to set it up to shoot the 33.95 Heavy's, so I reset the reg and hammer spring tension to shoot those pellets at the avg. V of 950 ft/s which is 68 ft lb energy.

So you can see from this example how much more versatile the best air rifle ever invented can be when re-powered with a new Huma engine! Sort of like putting a 427 Hemi in a Ford PInto! VaVooom!

All the best, Chuck
Click to expand...

Do you have videos of how to do all this, and other “ repairs” for the wildcat MK II. Specifically the 25 cal. Or a place that a newbie could get the CORRECT info. to change the reg, and other things that arise ? I would be interested in the 33.9 heavy as you stated above. 
 
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You all that replaced your reg’s, and have shots that start low and then after two or three they stabilize. Wait five minutes and it low again, it’s not necessarily any creep or anything wrong with the new reg. Chuck just scrolled me on this, and boy oh boy was he right!



cant post a video I took, but the port hole that used to be for the AMP adjustment had a tiny leak, enough to froth over a small squirt of leak detect solution. If I shoot shot after shot with no rest, FPS stays steady around 927-930. Wait the time it takes to lead up a magazine and cock/load, the velocity is at 880. Dropped that quick for the first shot. You all might wanna check for leaks on the plenum side of the reg.




 
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Hi Augie, please update us when you fix the leak. I'm interested in learning more about it. Normally a regulator has a seal on the high pressure side and one on the low pressure side, each of which is sealing against the atmosphere. Then there is a final seal that forms the valve seat. If either of the first two seals leaks, there will simply be a loss of pressure over time. Only a leak at the valve seat will affect velocity and that is the creep symptom that many people experience. Sounds like you guys may be describing something different.
 
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