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Please explain a regulator to a newb  

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josh3rd
(@josh3rd)
Joined: 2 years ago
Posts: 159
2020-02-19 11:34:08  

I understand the point of a regulator but how do you know what to set it at or what is or makes a good setting position.?


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pluric
(@pluric)
Joined: 2 years ago
Posts: 679
2020-02-19 12:16:04  

Google fu. Most manufacturers will have a preset for general use. If you are looking for more umph raise it some. You can search just about any model and get an idea what others have done, or not done to that specific gun. FX came out with a larger plenum for its Impact line. Now the regulator is being lowered from 140ish to between 90-110. Shot count went up because it's still on the reg to the lower number yet shooting at a higher speed because of more air being released from the larger plenum.

It's also based on what you are trying to tune the gun to do. If you are just plinking, punching short range paper lower the setting to save air and should be a bit quieter. Need more power for distance and pesting then up it some.

Look what some do with a hammer spring. Kind of the same thing. It's just adjusting a gun to what you would like it to do at it's best available adjustment option.

Keep in mind, I'm often full of shit. 😉 😀 


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nervoustrigger
(@nervoustrigger)
Joined: 2 years ago
Posts: 222
2020-02-19 12:23:11  

There are many ways to approach how to find a suitable setpoint. Too many to reasonably cover in a forum post. If you want to narrow the context a bit, I think you’ll get more useful replies. For example, if you’re wanting to take a unregulated PCP and install a regulator, one way to approach it is to plot a bell curve and determine at what pressure it’s producing maximum velocity and then set the regulator for approximately that pressure. Maybe 10% over that pressure actually to account for the fact the average pressure during the shot cycle will be less as a result of there being a smaller volume feeding the valve (plenum volume…the regulated chamber).

However in many cases that will not yield a particularly high shot count. Why? Well, let’s assume it’s a typical PCP with a 3000psi maximum working pressure. Odds are its bell curve peaks around 2500psi so if you set the regulator there, you only have 500psi to work with before the reservoir pressure falls below the setpoint. So generally what people do is open up the porting (enlarge air passages) so it will generate similar FPE at lower pressure. For example you may drill out the transfer port and tune it so the bell curve peaks around 1700psi and now you have a 1300psi pressure differential to work with.

But again, plenty more ways to approach it and even more ways to optimize or tweak for better performance.


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scratchit
(@scratchit)
Joined: 2 years ago
Posts: 182
2020-02-19 14:36:26  

@pluric

 

I’ve got a bit o’ that in me as well......

 

@joshIII:  I’ve not noted your presence in the head count thread ??

as ‘trigger noted, ya might get another set of answers depending on what you’re tryin’ to do.

More than one way to skin a cat.

 

Good form BTW......

 

ATB

 

 

...

 

 

 

 


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Gratewhitehuntr
(@gratewhitehuntr)
Joined: 2 years ago
Posts: 633
2020-02-20 09:37:18  
Posted by: @pluric

Keep in mind, I'm often full of shit. 😉 😀 

The world according to Pluric...


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josh3rd
(@josh3rd)
Joined: 2 years ago
Posts: 159
2020-02-20 09:43:27  

Well I just didn't understand about them and the optimization of em. like what makes people pick 1900psi as to 1500 or 2100 and so on


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scratchit
(@scratchit)
Joined: 2 years ago
Posts: 182
2020-02-20 09:48:34  

@josh3rd

 

that’s some deep kimchi there ....... hard to say in just a few words.

 

maybe someone else would like to give it a shot .....

 

ATB

 

 

 


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nervoustrigger
(@nervoustrigger)
Joined: 2 years ago
Posts: 222
2020-02-20 10:41:18  
Posted by: @josh3rd

Well I just didn't understand about them and the optimization of em. like what makes people pick 1900psi as to 1500 or 2100 and so on

Picking 1900psi under what circumstances?  Have to frame the question, give it some context or all I can do is engage in conjecture or attempt to answer all possible scenarios.  I’d love to help...but not that much 🙂


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scratchit
(@scratchit)
Joined: 2 years ago
Posts: 182
2020-02-20 11:03:16  

I’m w/‘trigger......

 

prob’ly shouldn’t think of me as “helpful”, toxic perhaps......

 

now that I’ve woken up the “dead”, or maybe got the ball rollin’, I’ll step back into the shadows.... soon.  Prob’ly best seen and not heard

 

might study on it a bit more, and come back with your question in the form of an answer, sorta like on jeopardy (grin)

 

ya got me goin’ son....

 

go ask LD (the real one, now), and pay real close attention !  Find some thread he’s involved in and get in the middle of it.....  If LD tells ya how to index your barrel, well that’s a good place to start.

 

caution, slow turtles....

 

don’t get my goat!


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Doug Wall
(@doug-wall)
Joined: 2 years ago
Posts: 128
2020-02-21 08:53:35  

A couple of things to keep in mind.

The purpose of a regulator is to keep the gun side of it at a constant pressure, while the tank side pressure decreases.

If you set a regulator at 1900psi instead of 1500psi, you will have quite a few LESS shots per fill, before it comes off the regulator.

If you play with the gun side parts (valve, plenum, transfer port, etc.), you can often increase power, and get more shot per fill at 1500 than 1900.

Take for a simple example a QB79 HPA. There are typically regulated at 1100psi, and there are lots of ways to optimize power. Granted, you will probably never get as much power as the "big guns"", but it's just an example.


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JW652
(@jw652)
Joined: 2 years ago
Posts: 62
2020-02-21 10:55:00  

   The simple answer to your question is that a regulator is designed to give consistent velocity from shot to shot. A decent reg can keep the extreme spread of shot velocity down to single digits. In precision shooting, such as FT, BR, or long range shooting, difference in velocity alone (es) can cause the point of impact on the same target to change vertically (hit high or low). If you have ever shot a CO2 gun, you have experienced a similar phenomenon in that as the CO2 gas pressure gets lower, shots become slower and weaker - changing the point of impact.

   In a pcp you fill a compressed air reservoir (bottle) - that is built into the gun to a pressure designated by the manufacturer for best performance. The working pressure of the rifle - the pressure the rifle needs to expel a pellet at a chosen velocity - is lower than the fill pressure of the onboard rifle tank and allows multiple shots. In a regulated rifle. the high pressure from the onboard tank goes first to the reg where it is reduced to a specific volume at a specific pressure before its journey through the transfer port  to the rear of the pellet and out the barrel. For example, The fill pressure may be 200 BAR (about 3000 psi), but the regulator may be set at 120 BAR - where the 120 BAR is the specific pressure needed to fire the pellet consistently at a desired velocity. Shots should be consistent until the tank pressure drops lower than the regulator pressure. This is called falling off the reg and results in an immediate , dramatic drop in velocity. The rifle will go from a 10 fps (for example) extreme spread to a huge shot to shot difference making remaining shots essentially useless as the pressure and velocity decline more and more with each shot. Once again, this is similar to what you may have experienced with a CO2 gun as it runs out of gas.

   An unregulated rifle - properly set up by the manufacturer or owner - has what is called a "shot curve". This means that pellets start at a chosen velocity and rise to a fairly consistent plateau - where it remains for a long string - until the pressure in the onboard bottle drops below the pressure at the plateau. At that point velocity drops off slowly until it reaches the starting velocity where most folks then recharge the rifle. For example, in one of my Theoben Rapid MK IIs, I want a plateau pressure of 875 - 890 fps fps which is an accuracy point for a lot of pellets. By setting hammer spring tension I can get a low start pressure of 865 fps which rises to the plateau velocity after about five shots and stays between 875 and 890 fps for about 70 shots before going back down to 865 fps. At 865 fps ( which I can tell by looking at a pressure gauge, or counting magazines - ie. six, 12 round .22 magazines equals 72 shots) I refill the rifle to 3000 psi and keep on shooting. It should be noted that the 25 fps extreme spread in this unregulated rifle does not make a perceptible change in the vertical point of impact at 50 yds.

   Setting up an unregulated rifle is easy to do if you have a chronograph. And many unregulated rifles are set up by the manufacturer to produce an optimum shot curve with a specific pellet that the manufacturer identifies and recommends.

   Dealing with adjustable regulators, slug liners and such for long range shooting is advanced DIY type stuff that can be confusing to even experienced pcp shooters. If your goal is to hunt small game, plink, or target shoot normal pellets out to 75 yds, you might want to consider a regulated or unregulated rifle pre-set at the factory. They have already done the work for you.

 

  

  


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scratchit
(@scratchit)
Joined: 2 years ago
Posts: 182
2020-02-21 13:05:54  
Posted by: @jw652

An unregulated rifle - properly set up by the manufacturer or owner - has what is called a "shot curve". This means that pellets start at a chosen velocity and rise to a fairly consistent plateau - where it remains for a long string - until the pressure in the onboard bottle drops below the pressure at the plateau. At that point velocity drops off slowly until it reaches the starting velocity where most folks then recharge the rifle. For example, in one of my Theoben Rapid MK IIs, I want a plateau pressure of 875 - 890 fps fps which is an accuracy point for a lot of pellets. By setting hammer spring tension I can get a low start pressure of 865 fps which rises to the plateau velocity after about five shots and stays between 875 and 890 fps for about 70 shots before going back down to 865 fps. At 865 fps ( which I can tell by looking at a pressure gauge, or counting magazines - ie. six, 12 round .22 magazines equals 72 shots) I refill the rifle to 3000 psi and keep on shooting. It should be noted that the 25 fps extreme spread in this unregulated rifle does not make a perceptible change in the vertical point of impact at 50 yds.

@joshIII

 

The whole post by “@jw652” is GOLDEN !!! Read it several times!  The gospel.  Oreilys in a nutshell!

 

Fiddly bits pose their own, unique, box of rocks.....

 

This should be the post of the year.  I don’t think anyone could have said it better.

 

oh, and if anybody ever asks, you send ‘em here and tell ‘em to read @JW652’s post.

 

 

scratchit

 

 

might have been apple, rarely helpful ...


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josh3rd
(@josh3rd)
Joined: 2 years ago
Posts: 159
2020-02-23 06:55:05  

JW and Doug, I truly appreciate you and everyone else for taking your time and passing on the knowledge.  JW i see that you said setting up an unregulated rifle is pretty easy. Can you tell me your way of doing so?  Much appreciate it


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JW652
(@jw652)
Joined: 2 years ago
Posts: 62
2020-02-23 11:47:46  

   It certainly helps to have a decent rifle to work with. I am old school and prefer the wood and steel Brit rifles that led the charge in pcp development around 1990. These were mostly rifles designed for the accuracy and reliability necessary to compete in FT - which was invented in the UK. At that time there was only one company using a rudimentary regulator - the "Sportsmatch GC-2 (named for the British airgun ballistition Gerald Cardew). It is the same company that you may recognize a top quality manufacturer of scope rings. It was expensive, but set the bar for quality - until the onboard tank of a single gun failed during a 200 BAR fill. No one was injured, but Sportsmatch decided it wasn't worth the risk and went back to making fine rings. Except for Nick Jenkinson who designed a regulated rifle for AA (NJR-100) and Rodney Boyce who sold Datstate Huntsman rifles with an aftermarket reg, most of the other pcp competitors set up their own unregulated rifles. It is these rifles that taught me proper setup. My way is not the only way, but it is tested and proven on these rifles. It also works with HW and older FX, Theoben, and Daystate models. Build quality is a key as a quarter turn of a screw or spring has to make a repeatable change that doesn't walk on you. Cannot vouch for inexpensive or Chinese rifles. It seems that a lot of folks expect to have to make modifications on an out of the box rifle just to make it work properly. I prefer to avoid the frustration and just enjoy the shooting part and often recommend the AA 410 rifle. You can purchase a good used one for under 500 USD. The design is simple, robust, reliable, and, accurate.      

   OK. You have chosen a rifle. The first  thing to do is read and reread the instruction manual from the manufacturer and follow their recommendations.  Next choose your goals: pellet, velocity. shot count, extreme spread, and etc. You will need a chronograph and a few hand tools (parallel tipped screwdrivers and allen wrenches). Your rifle needs to be properly scoped (an art in itself) and resting on bags on a sturdy bench with a table immediately in front of the bench at a height that allows you to shoot over the chronograph at a target. 25 yds works well. Fill the rifle to the recommended pressure - usually 200 BAR and shoot a long string after blowing off the first shot to settle the rifle. You should see a starting velocity that will rise for half a dozen shots and then stay fairly level (it will continue to rise gradually and then fall slowly) and observe the shot curve. You should see a plateau after the first few shots - where the velocity rises another 15-20 fps for 90% of the fill, and then gradually drops to the beginning plateau pressure and then more sharply to the starting velocity. That is your shot curve as currently set up. You now have an idea of the rifle's capability. If you find no shot curve and the velocities simply drop across the entire fill, you need to lower fill pressure until you get a curve.

   Velocity is a personal choice. I like velocity between 850 and 900 fps as it usually results in best accuracy and shot count over a fill. Lower starting velocity will usually give more shots and a longer plateau. Higher velocity creates a shorter, steeper curve. Extreme velocity results in few shots and, sometimes, no curve - just a straight velocity descent. A shot curve of 30 fps will produce negligible difference in poi at 50 yds.

   Velocity is controlled by either adjustable hammer spring tension or transfer port diameter adjustment - or both. Hammer spring tension is the usual method and generally requires an allen wrench turning a screw at the end of the receiver. This is the fiddly part -experimenting with spring and/or port adjustments and fill pressure. If you are lucky it will be pretty close to the way you want it as set up. At worst, you will spend a long afternoon shooting full rifle fills to get it right - but you will learn a lot. Shooting through the chrony at a target gives you practice and an idea of how well a pellet shoots. Just be aware that many pellets will shoot fine at 25 yds, but fall apart at 50. JSB, AA, and H&N usually give good long range results. Just as with inexpensive rifles, cheap pellets often present false economy.

   Enough. My head is pounding and eyes bleeding. Yours too, I expect. Once you have the procedure, it is trial and error. Just be patient. Also, I am sure others here will chime in with their suggestions, experiences and critical comments. Listen to everything and you will figure it out. And when you do, the magic will happen and the fun will begin.

                                                     Enjoy!

  

   

                                                                                                             

 


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josh3rd
(@josh3rd)
Joined: 2 years ago
Posts: 159
2020-02-23 12:28:16  

JW, how many children do you have?  Or better yet, can you make room for one more? That was some great feedback and truly appreciated. Thank you for taking the time to write that.  My eyes are not bleeding because you are a book full of knowledge and I love reading.  Thanl you


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scratchit
(@scratchit)
Joined: 2 years ago
Posts: 182
2020-02-23 15:53:00  

@jw652

 

my head hurts, my feet stink,.........,oh my Lordy that’s right!

 

 I couldn’t have done it.  Another required reading kind of thread.

 

JoshIII, you’re good, or you’re gonna be.....

 

ATB, All

 


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