How accurate are gauges on guns?

[Poke-E]

How accurate does everyone think the gauges on guns are? I have a TJ2 valve 9L tank, and alkin reg from top gun Airguns. When tethering my airforce Texan with an AAO upgrade the gauge and reg say 300 bar but the gauge on the gun is ready maxed out at 315. The gauge has to be off, correct ? Is there a way to get it calibrated?

Soooooooo, this was the problem all along. SMH! I shot about 100 rounds through my Texan trying to tune it and was wondering why my reg and gauge were so far off! Even shooting at 250 bar with my AAO kit I was slinging 350gr Nielson HPBT at 973 FPS!!!! Can't wait to see what it does on a full 300 bar and correct tuning!!!

 

[6gun]

How accurate does everyone think the gauges on guns are? I have a TJ2 valve 9L tank, and alkin reg from top gun Airguns. When tethering my airforce Texan with an AAO upgrade the gauge and reg say 300 bar but the gauge on the gun is ready maxed out at 315. The gauge has to be off, correct ? Is there a way to get it calibrated?

Short answer most of the small analog ones are not. Calibration is an option but not worth it really. I replaced my final reg guage with a digital, the resolution it can detect is beyond what is needed imho. Guages do wear out and get memory after a while. The cheaper the worse it is.

 

[blackdog899]

Where do you get this knowledge from? Serious question

 

[6gun]

Where do you get this knowledge from? Serious question

Life experience, growing up tuning paintball guns with a friend at a paintball shop when fiber wrapped cylinders were new. Being generally autistic about airguns for 30 years

 

[MongooseV8]

I can tell you the over seas gauges are very hit or miss. The Wika gauges are much more consistent and I trust them the most. The best you can do is measure several against each other, or use a calibrated gauge tester which pretty much nobody has.

 

[blackdog899]

Ok but what’s the standard that you test against? How off are they? There must be better info out there.

 

[MongooseV8]

Ok but what’s the standard that you test against? How off are they? There must be better info out there.

There are calibrated gauge testers you can measure against but they are very pricey so most people dont have those. They also need to be recalibrated occasionally like a torque wrench.

The cheap not as accurate alternative is to test against your other gauges. For example I have a GX CS3 pump that has a gauge, and when compared to my FX, Huma, Wika, Lieshy, Chinesium, etc; waaaaay off. When you have 10 Wika gauges that are all very close to each other, you can use that as your standard. And its easy to figure out which gauges are off high, or off low. Pretty much every other gauge reads different than all my Wika brand. Semantically speaking no gauge is accurate or the same as any other gauge. But you have to start somewhere.

Perfect? No of course not, but it works very well and is pretty close.

 

[BlackICE]

I have two Edgun gauges that I use as a standard. They read within 0.1 bar of each other. I connected them to a male Foster fitting and use it as a deadhead plug to "calibrate" other gauges.

 

[6gun]

Ok but what’s the standard that you test against? How off are they? There must be better info out there.

My question is, how precise? Precise relative to atmospheric, high resolution visually? Which position is this guage in functionally? How granular does your data need to be?

 

[Peashooter]

The 12 mm or so gauges on my friends snowpeak M30 seem off, or that is maybe not but the regulator is set to 150 BAR which seem high for a fairly long barrel .177 rifle.
Regulator changes more made by position of single grove adjustment screw more than needle movement.

 

[coastal drifter]

I have tested Wika, Huma and FX against my large oil filled SCUBA gauge and (all) are off a couple bar+- ... no big deal.

 

[Poke-E]

There are calibrated gauge testers you can measure against but they are very pricey so most people dont have those. They also need to be recalibrated occasionally like a torque wrench.

The cheap not as accurate alternative is to test against your other gauges. For example I have a GX CS3 pump that has a gauge, and when compared to my FX, Huma, Wika, Lieshy, Chinesium, etc; waaaaay off. When you have 10 Wika gauges that are all very close to each other, you can use that as your standard. And its easy to figure out which gauges are off high, or off low. Pretty much every other gauge reads different than all my Wika brand. Semantically speaking no gauge is accurate or the same as any other gauge. But you have to start somewhere.

Perfect? No of course not, but it works very well and is pretty close.

Sounds like sounds advice!!

 

[Firewalker]

Of the thousand or so 1" (or similar size) HPA gauges that have passed through the shop, all but the digital gauges have been simple spiral Bourdon tube gauges with no mechanism to re-calibrate or "true" the spiral if it is not displaying the actual pressure.

I chucked one up and cut it apart so you could see the insides. Almost all HPA gauges employ a spiral Bourdon tube, pressure transducers are used for most digital gauges while hybrid gauges using both the Bourdon tube and a digital gauge are available but are a poor substitute for the transducer type.

As far as accuracy goes, unless you have a test gauge that has been calibrated to test any Bourdon tube gauge against, you will be in the ball-park but not actually accurate. One can utilize a Sekhmet Digital Transducer Pressure Gauge to check other gauges but they are not certified calibrated off the shelf. They are however, very accurate for what they are.

A "cheat" I use is an Amazon Digital Transducer Pressure Gauge that I brought into work and had QA do a "calibration" on, it can't be certified or stickered but its tracking with the $50k calibration stand so it's good enough for me! Surprisingly, the 'cheap' Amazon gauge didn't have to be adjusted, it tracked along nicely with the test stand. Not bad for $106.00!

(Sorry, no pictures can be uploaded at this time)

 

[Trucker3573]

Then the question is if it is off is it consistently off. That is more important to me the consistency. As long as it is the same. When tuning over time you will know where you need to set the gauge for a given tune. As far as filling I believe there has to be some give in ratings. If a gauge is 10-20 bar off I highly doubt you are going to blow anything up. Overall I don’t think it is a major thing to worry about.

 

[6gun]

I have tested Wika, Huma and FX against my large oil filled SCUBA gauge and (all) are off a couple bar+- ... no big deal.

That's how I average out my data too.

 

[Poke-E]

Then the question is if it is off is it consistently off. That is more important to me the consistency. As long as it is the same. When tuning over time you will know where you need to set the gauge for a given tune. As far as filling I believe there has to be some give in ratings. If a gauge is 10-20 bar off I highly doubt you are going to blow anything up. Overall I don’t think it is a major thing to worry about.

You hit the nail on the head for me. In hindsight I should have worded my question differently. If the gauge is consistently off I'm okay with that as well, That is all I'm worried about! My main concern is the tuning aspect and not blowing myself up!!!!!! For tuning would you suggest just making my adjustments off of my external reg and making notes of where it reads on the gauge itself?

 

[Trucker3573]

You hit the nail on the head for me. In hindsight I should have worded my question differently. If the gauge is consistently off I'm okay with that as well, That is all I'm worried about! My main concern is the tuning aspect and not blowing myself up!!!!!! For tuning would you suggest just making my adjustments off of my external reg and making notes of where it reads on the gauge itself?

I think you can use either as long as every time you air it up both read consistently off from each other. That should put some confidence in using either. Just have to make the mental adjustment depending on what one you go by.

 

[6gun]

You hit the nail on the head for me. In hindsight I should have worded my question differently. If the gauge is consistently off I'm okay with that as well, That is all I'm worried about! My main concern is the tuning aspect and not blowing myself up!!!!!! For tuning would you suggest just making my adjustments off of my external reg and making notes of where it reads on the gauge itself?

Ooooooh, sorry. My recommendation is to de gas the gun, see if the needle is off of the stop pin when degassed. I've taken note of where it lies and just increased accordingly . If the guage is for general reference only it's no biggy. When tuning I follow all other signs more than a pressure guage number.

 

[Gerry52]

Answer to your 1st question, NOT VERY! In the ballpark, yes, but just how much is the real question. Filling tanks from my compressor there are 3 gauges involved (on compressor, on fill adapter & tank gauge). They're all within 100-200psi of each other so I just average it out & happy with it. The tolerance "window" of the 3 pieces of equipment will handle the pressures generated. Precise, standardized gauges that are EXACT are very expensive compared to what's on our equipment but we're still not dangerously pushing the safety envelope.

 

[6gun]

Answer to your 1st question, NOT VERY! In the ballpark, yes, but just how much is the real question. Filling tanks from my compressor there are 3 gauges involved (on compressor, on fill adapter & tank gauge). They're all within 100 bar of each other so I just average it out & happy with it. The tolerance "window" of the 3 pieces of equipment will handle the pressures generated. Precise, standardized gauges that are EXACT are very expensive compared to what's on our equipment but we're still not dangerously pushing the safety envelope.

Excellent advice. The more guages you have in line, the better sample group you get. Put at least one good guage on the fill side for safety. But there's overhead designed into all of this in case of a mistake. My Yong hengs and even cs3 all "sprung" their bourbon tubes in the guage so they were generally ignored.

As for op, what is this guage monitoring? Fill pressure or pressure to the breech? Either way, accuracy is preferable but not mandatory outside of good record keepingfor tunes and safety concerns on "the high side" of the air system. You have my interest.