Regulator Question

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IguanaPolice

IguanaPolice

Member
Aug 26, 2019
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Wellington, FL, United States
iguanapolice.com
I hope I haven't overlooked this question...

Consistency is one thing that a regulator is responsible for correct? If so, would it really matter what your tune is set up like? Good tune or bad tune, shouldn't the chrony show a small (low) extreme spread if the regulator is doing it's job, regardless of the power setting (if you have one)? 


 
Yes, no, maybe so. Its really not a straight answer. Regulator could be doing its job, but other parts not which produce larger variations than if they were. Regulator does its job when it provides consistent pressure behind the valve...but that doesn't necessarily mean you'll get consistently low spreads unless your valve is releasing near similar volumes at the pressure your regulator is set at...so its relational.
 
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So what's likely to cause an inconsistent pressure behind the valve if the reg is functioning properly?
Click to expand...


Creep, and its variance. Creep occurs over time until it hits its maximum, some guns are 1-2%, some 2-3%, others 5-6%...point is between shots, the longer you wait, the more variance / pressure difference your valve will have both holding it shut and ready to propel your next pellet forward.


So if you're hunting, and take 3 shots back to back, after the rifle has sat for awhile, and your true set point is 2000, but your regulator creeps to a maximum of 2100 @ 5% over a period of 1.5 hrs. Well your first shot will be 2100 provided you don't do any dry fires, shot 2 may be 2050, and shot 3 may be at 2000...and if you wait 30 minutes for your next shot, it may be 2030, where as a shot that you wait 60 minutes to take may be 2060....



That and temperature will be your largest factors in pressure variance. The amount of creep your regulator exhibits, depends on the RMS of the material in use, and the degree to which your seat and piston may be out of round, but that in itself is no certainty to eliminate all creep, as the slightest nick or imperfection in the knife edge of your piston, or piece of dirt/debris can cause creep considering the air molecules in your pcp are around .0001 microns big. There are 1000 microns per millimeter... so essentially to the order of a millionth of a millimeter if I do my half arsed math correctly...




 
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So what's likely to cause an inconsistent pressure behind the valve if the reg is functioning properly?
Click to expand...


Creep, and its variance. Creep occurs over time until it hits its maximum, some guns are 1-2%, some 2-3%, others 5-6%...point is between shots, the longer you wait, the more variance / pressure difference your valve will have both holding it shut and ready to propel your next pellet forward.


So if you're hunting, and take 3 shots back to back, after the rifle has sat for awhile, and your true set point is 2000, but your regulator creeps to a maximum of 2100 @ 5% over a period of 1.5 hrs. Well your first shot will be 2100 provided you don't do any dry fires, shot 2 may be 2050, and shot 3 may be at 2000...and if you wait 30 minutes for your next shot, it may be 2030, where as a shot that you wait 60 minutes to take may be 2060....



That and temperature will be your largest factors in pressure variance. The amount of creep your regulator exhibits, depends on the RMS of the material in use, and the degree to which your seat and piston may be out of round, but that in itself is no certainty to eliminate all creep, as the slightest nick or imperfection in the knife edge of your piston, or piece of dirt/debris can cause creep considering the air molecules in your pcp are around .0001 microns big. There are 1000 microns per millimeter... so essentially to the order of a millionth of a millimeter if I do my half arsed math correctly...



Click to expand...

Here's a really good one for you... If that reg creep is constant say nominal 2000psi sit more than 2 hours creeps to 2100 that shots gonna be somewhat astray right? Maybe next shot after is minimally astray too and you know shot 3 WILL BE SPOT ON. What if you map those first 2 errant shots on paper then manually compensate for those FIRST 2 CREPT SHOTS? Do you think those first predictable errant shots can be compensated for by say clicking the turret 10 up and 5 left then followed by readjust 5 down and 3 right then at shot 3 click 5 down and 2 right which is original zero? Of course you can holdover through the reticle so poi can be guesstimate? Thoughts? Yo!
 
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I hope I haven't overlooked this question...

Consistency is one thing that a regulator is responsible for correct? If so, would it really matter what your tune is set up like? Good tune or bad tune, shouldn't the chrony show a small (low) extreme spread if the regulator is doing it's job, regardless of the power setting (if you have one)? 

Click to expand...

I will take a shot at answering this. A regulated gun will have a longer shot string with a tighter ES when filled to the guns max pressure than the same gun without a reg. Even with a bad tune. Now here is what makes a reg shine. Once you get your hammer strike to be perfect and your valve lift and dwell if so desired, you can take that 20fps spread and make it 5fps. Now your gun will sip air and be even friendlier to shoot than the unregulated gun that is trying to control things over a broad psi range. Yes you can get a bunch of shots out of gun without a reg but your long shot string looks like a tire going flat.
 
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So what's likely to cause an inconsistent pressure behind the valve if the reg is functioning properly?
Click to expand...


Creep, and its variance. Creep occurs over time until it hits its maximum, some guns are 1-2%, some 2-3%, others 5-6%...point is between shots, the longer you wait, the more variance / pressure difference your valve will have both holding it shut and ready to propel your next pellet forward.


So if you're hunting, and take 3 shots back to back, after the rifle has sat for awhile, and your true set point is 2000, but your regulator creeps to a maximum of 2100 @ 5% over a period of 1.5 hrs. Well your first shot will be 2100 provided you don't do any dry fires, shot 2 may be 2050, and shot 3 may be at 2000...and if you wait 30 minutes for your next shot, it may be 2030, where as a shot that you wait 60 minutes to take may be 2060....



That and temperature will be your largest factors in pressure variance. The amount of creep your regulator exhibits, depends on the RMS of the material in use, and the degree to which your seat and piston may be out of round, but that in itself is no certainty to eliminate all creep, as the slightest nick or imperfection in the knife edge of your piston, or piece of dirt/debris can cause creep considering the air molecules in your pcp are around .0001 microns big. There are 1000 microns per millimeter... so essentially to the order of a millionth of a millimeter if I do my half arsed math correctly...



Click to expand...

Here's a really good one for you... If that reg creep is constant say nominal 2000psi sit more than 2 hours creeps to 2100 that shots gonna be somewhat astray right? Maybe next shot after is minimally astray too and you know shot 3 WILL BE SPOT ON. What if you map those first 2 errant shots on paper then manually compensate for those FIRST 2 CREPT SHOTS? Do you think those first predictable errant shots can be compensated for by say clicking the turret 10 up and 5 left then followed by readjust 5 down and 3 right then at shot 3 click 5 down and 2 right which is original zero? Of course you can holdover through the reticle so poi can be guesstimate? Thoughts? Yo!
Click to expand...



Sure, really hard to do as I said when your shot time varies between shots...on the bench, plinking, or over the chrony are different than adding a time differential into an equation that takes it into consideration. There are methods of tuning that deal with nominal creep, where no compensation or dry fire is needed to ensure precise shot placement/shot consistency.


At most ranges under 100 yards a minimal amount of creep shouldn't send your shot astray too far. I'd prefer to tune and buffer out that variance then compensate with POA changes.
 
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If you have the time and patience, try sorting, weighing and measuring head size of your ammo if you haven't done so to weed out the variances and start from there. Record the atmospheric conditions once you have the right tune. On a random day in the same location or same altitude, break out the chrony and record the first few shots and note the temperature of the day.
 
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Lots of great points and advise guys. The trend seems to be that my most errant gun shoots high for two shots, then is spot on. After ~10 shots, POI is way off (Elevation and windage) but consistently accurate with new POI. Also when I switch magazines or use a different power setting and return to the previous power setting, my POI is off from before.

BTW, I have sorted pellets and generally speaking my groups are tighter until she goes astray. 
 
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Below is a Copy & Paste snippet from a thread over on the GTA I made some time ago. It was ADVANCED REGULATOR TUNING TECHNIQUES.






Ideally .... having the tools to do so ( Remote ACCURATE pressure gauge fit between fill tank and guns tank. ) would be best done IN YOUR SITUATION by first reducing the spring energy on hammer a far amount before proceeding. having a few springs of differing rate handy you may need. During test you may need to go up or down in rate to find the sweet spot.
Then get the guns air tank drained down to 80 bar or so. LEAVE REG set point where it is at for now !

Hook up the gun to fill tank with gauge in the line. Fill the guns tank in 10 bar increments starting at @ 80 bar and take 2 shots over the chrony and write down pressure / speed. Continue to do this watching where the speed plateau is and do a few 10+ bars past to confirm at what pressure the speed peaks. *** IF THAT does not happen when getting to the pressure regulator is set for YOU STILL HAVE TOO MUCH SPRING.

IF by chance you can NOT get enough speed with pressure all the way up to the known set point, Not enough spring

Under stand you already know that at a pressure LOWER than current set point you can make more power than wanted, so it is just a matter of finding at what spring rate and pressure the gun will find the speed you want.

So now lets assume with a reduced spring rate that in your 10 bar incremental testing the gun hits your 865 fps target speed for 30 ft lb ( 18 grains ) at @ 110 bar and shoots slower at higher pressure .... Now you have establish where the natural bell curve is.

Dump the air from test gear, dump the guns tank and dismantle removing regulator. In a test fixture or what ever miens you have SET THE REGULATOR to @ 1-2 bar less than pressure you peaked at.

Set as such the gun will shoot at the prescribed speed, come off regulation at the same speed and even if you get a tad bit of reg creep letting gun sit ... THE SAME SPEED.
And ... you will find more usable shots per fill period.


My little tidbit of advanced regulation tuning technique

Good luck.
Scott S
 
Upvote 0
Below is a Copy & Paste snippet from a thread over on the GTA I made some time ago. It was ADVANCED REGULATOR TUNING TECHNIQUES.






Ideally .... having the tools to do so ( Remote ACCURATE pressure gauge fit between fill tank and guns tank. ) would be best done IN YOUR SITUATION by first reducing the spring energy on hammer a far amount before proceeding. having a few springs of differing rate handy you may need. During test you may need to go up or down in rate to find the sweet spot.
Then get the guns air tank drained down to 80 bar or so. LEAVE REG set point where it is at for now !

Hook up the gun to fill tank with gauge in the line. Fill the guns tank in 10 bar increments starting at @ 80 bar and take 2 shots over the chrony and write down pressure / speed. Continue to do this watching where the speed plateau is and do a few 10+ bars past to confirm at what pressure the speed peaks. *** IF THAT does not happen when getting to the pressure regulator is set for YOU STILL HAVE TOO MUCH SPRING.

IF by chance you can NOT get enough speed with pressure all the way up to the known set point, Not enough spring

Under stand you already know that at a pressure LOWER than current set point you can make more power than wanted, so it is just a matter of finding at what spring rate and pressure the gun will find the speed you want.

So now lets assume with a reduced spring rate that in your 10 bar incremental testing the gun hits your 865 fps target speed for 30 ft lb ( 18 grains ) at @ 110 bar and shoots slower at higher pressure .... Now you have establish where the natural bell curve is.

Dump the air from test gear, dump the guns tank and dismantle removing regulator. In a test fixture or what ever miens you have SET THE REGULATOR to @ 1-2 bar less than pressure you peaked at.

Set as such the gun will shoot at the prescribed speed, come off regulation at the same speed and even if you get a tad bit of reg creep letting gun sit ... THE SAME SPEED.
And ... you will find more usable shots per fill period.


My little tidbit of advanced regulation tuning technique

Good luck.
Scott S
Click to expand...

I do something similar to that very good tutorial. Only difference with me is I specifically shoot for accuracy and set the reg pressure right at that spot that gave smallest tightest single hole groups for best accuracy instead let the pellets do the talking instead because the pellets and speed harmony go hand in hand and all guns are different even being from the same manufacturer and model as well as caliber. Yo!
 
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just a quick addition .....



If your starting from scratch perhaps after a servicing ... or have access to regulators setting such as some FX, WAR etc guns, would advise setting the reg pressure ( Set Point ) ABOVE where you likely need it. In this way with the testing data the regulators function is removed, tho plenum volume remains and finding the ideal PRESSURE as well HAMMER STRIKE for the POWER wanted will be easier to archive.



Scott S
 
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There are many ways to skin the cat with tuning in a pcp...not really going to speak to superiority of one method over another, but I'll agree with YO that whatever gives you the best accuracy at the end of the day is ideal, it doesn't matter which road you drive to get to that destination.



I don't tune to my hammer weight or hammer spring, I tune my hammer spring and weight to my needs.



I don't tune my pressure to accommodate my hammer weight or spring. I tuned my pressure to give me the energy output I desire.



Simple rather.
 
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