Overfilled PCP - Now Reg Pressure Drastically Dropped

[kennyc]

I posted this on another forum, and I'm posting it here as well.


Hey Folks, I need some help here. Like a fool, I trusted the auto shut off on the compressor I use to fill my guns with, and one of my Artemis P15's pressure gauge was maxed out when I noticed it hadn't shut off. Now the gun only shoots at about 750 fps, as apposed to the 850 fps it used to shoot. There are no external air leaks. I put the gun aside for the past few months and today I tore it apart and replaced the regulator (set at 120) with a huma I had lying around. I refilled it and started shooting and it was shooting at around 880. I adjusted the hammer spring and got it down to shooting at 850, and it was stacking pellets again at 50 yards (JSB 18gr) like it used to. (Yeah, I won the barrel lottery on this one!)

Anyway, after a dozen shots it started dropping off again and within another 10 shots it's only shooting 750 fps again. As I said, there are no external leaks. The gun sat for the past 4 months and the pressure gauge never dropped. I can't figure out what is causing the issue, but I wonder if the air cylinder slightly expanded when it was over filled and air is leaking internally somewhere. I would appreciate any help you folks have to offer. Thanks!

[PasadenaMike]

After you installed the huma and it settled in at 750 is it consistently staying at this velocity ?

[kennyc]

Geeze, I can't believe I forgot to mention the caliber. It's a 22. It didn't settle at 750, the velocities keep falling off. As I said, the problem started when it was overfilled, not a regulator setting. The Huma reg was one that I had already installed in the gun months ago, but I thought my ex girlfriend might take the gun with her after we broke up (it was her gun) so I took the huma out and installed the original again. The gun shot just fine until I overfilled it, and it did the same thing with the original reg in it, so I replaced it with the huma hoping that the reg was the problem.

The problem has to do with the gun being overfilled, I just can't figure out where the issue is. I have to wonder if the air cylinder got slightly stretched from the over fill, and the reg o-ring isn't dealing properly now... I'm sure someone else has experienced this before.

[ezman604]

Moved to PCP Gate.

[avator]

I don't know alot about the inner workings of a regulator other than what I've read here on the GTA but I would suspect that things inside the reg may have become deformed under the pressure.

[happymecanic]

Soapy water can help resolve many mysterious issues.

[sb327]

Does this gun have a gauge on the regulator side?

When you fill the gun, does the reservoir gauge match your compressor?  If you over pressure these little gauges, they tend to read higher than actual.

The fact it does this later in the string and with two separate regs, seems to point at no internal leaks. How much over was it filled?

Dave

[tennx]

I got nuttin but good luck…but I did learn something …dont trust auto-stop (which Im bad about) …stay with the gun….Im sure I read that on here somewhere..lol

[triggertreat]

I would say the higher pressure changed the reg seat position.  It should just be a matter of adjusting the reg set point again. 

[TorqueMaster]

If I'm not misreading the problem, I think some of you missed that OP replaced the regulator AFTER the overfill.  But the same problem remains.  Two bad regulators failing the exact same way?

Following up on sb327:
"When you fill the gun, does the reservoir gauge match your compressor?  If you over pressure these little gauges, they tend to read higher than actual."

Could it be your gun's gauge is now broken, reading high, and you are not getting a full fill?  You may be off reg, don't know it, and the velocity keeps dropping...?

[avator]

If I'm not misreading the problem, I think some of you missed that OP replaced the regulator AFTER the overfill.  But the same problem remains.  Two bad regulators failing the exact same way?

Following up on sb327:
"When you fill the gun, does the reservoir gauge match your compressor?  If you over pressure these little gauges, they tend to read higher than actual."

Could it be your gun's gauge is now broken, reading high, and you are not getting a full fill?  You may be off reg, don't know it, and the velocity keeps dropping...?

Good catch Bob.

[Corny]

I would suspect the regs

For sure u need to rule out that it’s not the reg.
Do u have some means of actually testing what the reg is doing?

[triggertreat]

Most likely the Huma reg settled in and needs to be readjusted now or the hammer energy needs to be readjusted.  It could also be that the Huma is creeping.  If so, you should see lower velocities in the beginning of the shot string and then higher velocities after a few shots in.

[PasadenaMike]

Most likely the Huma reg settled in and needs to be readjusted now or the hammer energy needs to be readjusted.  It could also be that the Huma is creeping.  If so, you should see lower velocities in the beginning of the shot string and then higher velocities after a few shots in.

Kinda what I’m thinking too

[3crows]

I can't figure out what is causing the issue, but I wonder if the air cylinder slightly expanded when it was over filled and air is leaking internally somewhere. I would appreciate any help you folks have to offer. Thanks!

If you over filled such that the air cylinder "expanded" then you have worse problems than just a regulator. You might want to give that one back to the ex if you do not like her much anymore  .

I think your regulators are creeping up and as the pressure increases in the plenum the valve which is tuned for regulated pressure results in the velocity fall off.

[avator]

I doubt this has anything to do with your issue but just more of an observation..
If you overfilled the gun and maxed out the gauge, I can't help but wonder if your compressor was affected as well.
What is the "maxed out" number on the gauge? What compressor do you have?

[avator]

Nevermind.... if that's a normal Artemis 300 bar gauge the 4350 ish psi is well within the range of most compressors.
Besides, a burst disc would have let go if things were too extreme.

[JPSAXNC]

You've tried three different reg's and the gun does the same thing, it's probably not the reg. Air cylinder expanded? it wouldn't make any difference to the pressure. It sounds like a slow leak, or other mechanical issue.

[Bentong]

When you empty the tank..does the dial settle all the way left, if not you'll need a new guage so you can top off the tank to spec..could be reason you drop off reg setting with just a few shots.