Precharged pneumatics, regulators and power adjusters: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2

This report covers:

    • Power adjustment
    • Striker (hammer) blow
    • Understand?
    • Transfer port control
    • Michael — this is for you
    • Stability
    • Finally — how practical is adjusting power?
    • Summary

Today I will try to finish my answer to Michael about power adjusters on precharged pneumatics (PCP), which I have broadened to include air regulators. Please read Parts 1 and 2 to see what has gone before.

Power adjustment

Michael, there are several things an owner can do to adjust the power of his PCP. A longer barrel will often increase power, but that’s not immediately within the owner’s grasp. We are talking about adjusting power of a specific gun by means of things that are easy to do, without changing or modifying the rifle.

Striker (hammer) blow

Power can be adjusted easily by controlling the striker blow to the firing valve. A harder blow will force the valve open wider or for a slightly longer time. Either one of those or both of them means that more compressed air can flow out of the reservoir to power the pellet. As long as the pellet is inside the barrel, the more compressed air that gets behind it to push it, the faster it will go.

The weight of the striker is fixed. A heavier striker could apply more force to the valve stem, but I have not seen a system where the user was able to change the striker weight on the fly. That leaves either adjusting the striker spring tension, or the length of the striker’s travel as the only two ways of adjusting power. The simplest method of adjustment is by increasing and decreasing the tension on the striker spring. This is done with a threaded screw of some kind that presses on the end of the spring opposite the end that’s in contact with the striker.

Spring tension adjustment
In the graphic above the spring at the top is relaxed for a less powerful strike. When the spring is compressed, the striker hits the valve harder.

If you can adjust the length of the striker’s stroke, you increase its inertia. That increases the force with which it hits the firing valve.

Understand?

That should be very clear and obvious. But bear in mind that if there isn’t much compressed air in the reservoir, you can hit that valve as hard as you want and nothing more will happen. Or, if the valve only opens so far, you can hit it hard enough to destroy it and still get no more power. The striker can only control power so far before it runs out of capability.

Transfer port control

A better way for the user to control power in a PCP is to control the size of the air transfer port. That’s the same as controlling the gate at a rock concert. There may be thousands of people waiting to get in, but the size and efficiency of the gate controls how fast the auditorium fills. Control the size of the air transfer port and you control how much air can flow through in the time the pellet remains inside the barrel — which is the only time that matters.

Transfer port
The transfer port on top is wide open and will pass as much air as possible in the time the valve is open. The port on the bottom has been restricted and can only pass a fraction of the air.

The restriction can be as simple as a screw that intrudes into the transfer port. Anything that hinders the flow of air will work. Some guns have definite power settings, while others have an infinite adjustment between the two limits.

Michael — this is for you

The Benjamin Marauder, has all of these adjustments. That’s quite uncommon. I agree that the way the Marauder adjustments work — via hex screws buried inside the receiver — neither adjustment is as easy to make as those found on some other guns. But the Marauder gives you adjustment flexibility that surpasses most other PCPs. However, that higher flexibility brings in some complexity.

As you adjust the Marauder, since you are adjusting the power of the striker via its spring and also the length of the stroke, plus controlling the air flow through the transfer port, you are changing the optimum air pressure range at which the rifle operates. Simply stated — you’re changing the fill pressure of the rifle. It would be wonderful if this could be done with a single external adjustment knob, but it can’t. The power of the striker and the efficiency of the air flow through the transfer port are interdependent. Each one affects the other.

Think of this like an audio amplifier that also has equalization. You can adjust the highs and lows, but if you change the volume, the highs and lows need to change, too.

Stability

The last subject I will cover is stability through the range of adjustments. Some PCPs are very stable (small velocity variances) when they are in a certain range of their power adjustments. The TalonSS, and in fact all AirForce sporting rifles, like the medium to high part of their power range. Velocity may vary by less than 20 f.p.s. in that part of the power range, but if the power goes to the lowest level the variance may open to 40 to 60 f.p.s. You’ll get more shots, but they will also vary more. However, install a MicroMeter tank and that turns around. That’s because the AirForce tanks are where the firing valves live, and they are tuned for what is expected from that tank.

Finally — how practical is adjusting power?

This is the advice that GunFun1 gave Michael about adjusting airgun power. I would have said something similar.

Michael,
Think about this also with the power adjustment. Yep it’s easy to dial the power down for the pest bird in the yard and up more for the squirrel out at 60 yards.

But here’s what to think about. What happens to POI/point of impact when the power is changed? It goes up or down. So that means now you have a gun whose shifting impacts at different power settings need to be learned.

I use to do that with my first Talon SS and Marauder. But I found out after time that it’s best to tune the gun for what velocity and fill pressure you want and leave it alone. In other words don’t keep changing the gun settings for a particular time of shooting.You get a much more consistent gun that way by leaving it set at that particular setting. And, what I mean by that is a accurate gun and a accurate person shooting that gun.

When you’re pesting or hunting you need to know where that pellets going to hit in relation to where you aim. Sometimes it’s hard enough learning the holdover or under at one setting, let alone multiple power settings.

I will just add this. It used to be popular to have a rifle and pistol that were chambered for the same cartridge. People said if you ran out of rifle ammo, just use your pistol ammo. Sounds nice and neat, doesn’t it? Well — it isn’t! It’s messy. A rifle handles a cartridge completely different than a handgun, and instead of using the same round in both what you end up doing is compromising. Your ammo doesn’t work as well as it could in either the rifle or the pistol.

Summary

In this series we have talked about pressure regulators and what they can and cannot do. Then we talked about balancing a valve to operate within a certain pressure range. Finally we talked about power adjustments — what is done to make them work and how they affect the performance of the rifle.

If you remember nothing else, take this away. A regulator works best when it is set at the pressure the airgun works best at. Anything less and the reg. is just along for the ride.

103 thoughts on “Precharged pneumatics, regulators and power adjusters: Part 3

  1. B.B.,

    Well you did it again. That was very clear and concise. I need to read this every time I think about changing the knobs on my Marauder. I keep thinking I can get it to be accurate over a larger fill band and it just keeps shifting the band. You have said this before but it is hard to resist with all those knobs.

    I hope this time it sinks in.

    Don


    • Don,

      What about fitting an after-market regulator to your Marauder? That would flatten the bell curve and increase the consistent shot count. Would let you use a full pressure fill instead of what is needed to suit the curve.

      Hank



      • Hank,

        I realy don’t need a regulator on my Marauder, it is set up the way I like it. My whole problem is leaving the settings alone. Just my nature I guess.

        Went fishing today, got skunked. Still a fun day.

        Don


        • Don,

          I keep my eyes open for a deal on a .22 Marauder – would like one for its tinker-value, they are great rifles.

          Yeah, know what you mean – it is set-up great and making one more little adjustment would make it that much better 🙂 Been there, done that – got to start over again. Something about the laws of diminishing returns eh?

          Sorry to hear that the fish weren’t cooperating, glad you got out. I’m envious of the places that have open water – won’t have any of that until at least the end of March around here. Winter is going to seem extra long this year – just got a new fly rod and am going to try spey casting big flies for pike.

          I’m wishing hard for an early spring but the skiers are wishing just as hard for the opposite.

          Hank


          • Hank,

            I had a friend that was a master at tying flies. He also tied trolling flies that mimicked a minnow. They were too nice to fish with.

            I have way too many fishing polls that have been sitting for way too long. Maybe this year I will do more fishing.

            Good luck on the Marauder. When someone shoots mine they are usually surprised at how well it shoots. I think most folks that get one seem to hang on to it.
            Don



            • GF1,

              I bought the .25 FX Royale 500 for larger pests (woodchuck and raccoon sized) and longer range shooting so I have that well covered.

              I would stick to .22 for the Marauder as it would be used for plinking and target shooting up to 55 yards on my shooting range. Doesn’t need to be .25 for those duties and the .22 is a lot less expensive.

              Hank


              • Hank
                Ok don’t remember you saying you had that .25 caliber.

                But you might consider a .177 Marauder instead of a .22. There have been mixed results on accuracy with the .22 caliber Marauder’s. But not the Marauder pistols. They are accurate.

                The .177 Marauder’s are a very accurate out to 60 yards. There is a lot of people that use them for feild target. And I have taken many squirrel out to 60 yards with the one s I had.

                Don’t underestimate the .177 Marauder. They are very capable of doing the jobs I just mentioned.


    • Don
      I agree about all the adjustments on a Marauder being tempting to move. But really what’s nice about the Marauder is you have the luxury of picking your fill pressure so to speak.

      Maybe someone with a buddy bottle or automatic compressor could choose a higher fill pressure and adjust the striker and stroke a little heavier. And probably the transfer port hole a little more closed.

      But if your hand pumping you could tune the Marauder to a lower fill pressure. It would be just the opposite in a sense than the high pressure tune. A lighter striker pressure and less stroke. And probably a little more open on the transfer port adjustment to keep the air flow up.

      So yep the adjustments are nice. But once you get it tuned for the pressure you want to fill to and the velocity you want from the transfer port hole. It’s time to leave it alone.


      • GF1,

        I have a large bottle now and don’t have to worry about the filling or pressure like I did when pumping. I am getting twenty good shots on a 3000 psi fill. So I made the adjustments you mentioned. Before I was filling to 2600 psi with the pump.

        Twenty good shots is all I need on a fill. I just can’t help but turn a knob even when I know I shouldn’t unless I want to go through the whole process again.

        I will be looking at the Fortitude with the regulator. It looks like a fun gun.

        Don


        • Don
          Believe me I know what you mean about the knob turning.

          I’ll tell you the truth as good as the Discovery and Maximus work right out of the box. I think they are much more enjoyable than trying to tune in a Marauder set up. Fill them and shoot. Sometimes simple is better. 🙂


  2. B.B.,

    Very nice. From personal experience with the Maximus in .22:

    Installing a regulator and filling to 3000 allowed me to get 27 shots with a 12 fps spread, 780 fps average.
    (Prior, 27 shots yielded a 100 fps spread)
    So, I will take that.

    Gunfun did the same thing, but also added a lighter 1322 hammer spring. He says that he is getting:
    65 shots per fill and getting 750 fps average (whereas I am getting 780 fps)
    Spread?

    Either way, assuming we have the regulators set the same, or near same, there appears to be an added benefit to a lighter hammer spring (increased shot count with a 30 fps loss), which I plan to try.

    At any rate, there is some real world tuning and direct effects, which,…. all goes back to your statement of finding just what is the (best) setting for that particular gun and valve. I am in the “set it and leave it” camp by the way. But gosh B.B.,.. all those knobs and adjustment are just so darn cool to play with! 😉 The flip side?,… you can drive yourself nuts!,.. so it does help to have an idea of what does what and what to expect when you go’a messin’ around. Your series has helped us with that.

    Good Day to you and to all,…… Chris



      • Jim
        When I put the regulator in my Maximus I went up to 3000 psi to get shot count. Chris did his Maximus after I did mine. He tuned just to get a closer fps spread and not necessarily shot count. So he needed to go to 3000 psi to get back shot count also.

        The big difference in Chris’s tune verses mine is I have a much lower working pressure that the regulator is set at. What it boils down to is my tune is more efficient with air use than Chris’s tune.

        But I guess what matters in the end that we both are happy with what we have. We are just using the regulator in different ways.


        • Chris / GF1,

          Is it safe to run 3000 psi in a gun designed for 2000 psi?

          What modifications did you have to make to run the Maximus at 3000 PSI?

          Just curious,

          Jim


          • Jim
            Chris explained it good about the higher fill pressures. And yes I have pushed some pcp’s to the limit I do believe. Well maybe not. But definitely giving them a air gun version of a stress test. 🙂


      • Jim,

        Gunfun explained the 3000 fairly well. It is safe at that pressure and tested beyond that. They do sell stainless steel replacement screws that have a higher sheer strength. I will be getting some. Mine is also regulated, since I added one, so the valve is not seeing 3000.

        I suppose there is safety concerns with most any product and one should do there own research to arrive at (their own) particular course of action, or lack thereof.

        Gunfun could elaborate more, I am sure. Works fine and no problems.


        • Chris,

          Thank you for your response. I was concerned with safety in running the cylinder at 150% of its working pressure but it looks like you and GF1 have taken care of that concern.

          Jim


          • Jim,

            Well, I would not go so far as to say the (GF1 and I) have taken care of any concerns. It works. GF can say more I am sure. Most things are tested well above 150%,… just for people like us that are going to push the limits. It may be best to (only) do it with a regulated rifle though?,.. but I am not sure on that. Maybe GF will chime in? The .25 -rod has been running at 3400-3500 with a heavier hammer spring just fine. Just another example of pushing the limits.

            Thank you for your concern.


        • Chris
          I just caught this. Your valve is still holding 3000 from coming out the back of the gun. It doesn’t have 3000 psi feeding through it. But it does have 3000 psi pushing against it because the regulator and and spacer and gauge block assembly rest up against it.

          Just wanted to mention that incase yo didn’t notice.


    • Chris
      I’m averaging about 10-12 fps since the regulator and striker spring has settled in.

      And what I did is lowered the working pressure in my Maximus. I think you got your regulator at 1200 or 1400 psi. I don’t remember which right now. But I have my regulator set at 800 psi. So that’s why my 1322 striker spring works to get the velocity and shot count I want.

      Basically the striker spring has the right amount of pressure to let enough air out of the valve to send the air to the transfer port opening to send the pellet flying at the velocity I want. If the velocity was lower than I want I could do two things.

      That would be adjust the spring pressure heavier if I had a adjustment or put a little heavier striker spring in. That would probably lower the shot count a little that way.

      The other thing I could do is try a little bigger hole in the transfer port opening. That will not increase velocity that much though on the Maximus because they already have the hole pretty big.

      And obviously if I wanted a little less velocity I would go the opposite and go lighter on the striker pressure or a smaller transfer port hole.

      So the whole reason my tune is getting the shot count I’m getting is cause of the lower operating pressure. Basically I have 3000 psi down to 800 psi of air. And with the lower operating pressure my valve just sips air for each shot. You tune you only have 3000 down to 1400 psi. Which is 600 psi less air available to use. Plus your hitting your valve harder with the heavy spring to get enough air to the pellet. So basically your gun is still gulping air. My gun is sipping air.

      Yep that’s what is cool about the regulator. You can choose your working pressure. Then it’s up to you to fill to whatever you want. Possibly a lower full fill if you hand pump or a higher fill pressure for a buddy bottle or compressor. Your just reducing or increasing shot count.


      • GF1,

        Yup, I need to get off my butt and order a Custom Shop 2240 and a Maximus barrel and some other goodies. 1322 spring in the plans. 10-12 spread is good. That new Fortitude really has me “burned”. Dang, that is just what I wanted. Final change/upgrade,… thumbhole/pistol grip it and keep the forend the same. Oh yea,…. toss in a cheek riser. Separate/new stock upgrade I am thinking.


        • Chris
          I’m surely you could probably sale your Maximus.

          But on the other hand. We still really don’t know how accurate the Fortitude is going to be. They say it uses the same barrel making process that the Maximus uses. But won’t really know till some guns get out to the public.

          And I’ll tell you the truth. My Maximus has always been rediculous accurate. I can not get rid of that gun. Even if I do get a Fortitude and it turns out accurate.


  3. BB,

    It does indeed sound like not having easily adjusted knobs and such is the way to go. As in the Marauder, you can fine tune it to what you want, but it is not too easy to change the settings “on the fly” which can end up driving you gaga.



  4. BB,
    I really liked the 3 power levels of the FX Gladiator and Cyclone. Those are two rifles I wish I had not sold. Three power levels seemed like just the right amount and it wasn’t too hard to remember the range where each power level was dead on. In my backyard I would shoot on low power and got a ton of shots.

    David Enoch


  5. Transfer Port Control-

    When you do this don’t you mess up the air flow path. Isn’t this just like having a burr in a springer’s transfer port?
    Or, are the pressures so high, that air path does not matter, just air pressure and volume are important?

    Thanks,

    -Yogi


  6. Mr. Gaylord:
    This has been a very interesting and very technical series of posts. You talked about transfer ports today. What effect, if any, does air turbulence and laminar flow factor into how a rifle operates?
    The Airforce rifles have the air tank straight behind the chamber while most other rifles have the tank forward and the air has to make a sharp turn to get behind the pellet.
    Doesn’t this introduce turbulence and laminar flow issues into the mix? Is this of any significance in the overall question of adjustabiliy?
    Respectfully submitted
    William Schooley
    Rifle Coach
    Crew 357
    Chelsea, MI


    • William,

      Airflow does play a part in all of this. However, the biggest part it plays is when you are going for the most power. Then the straight path and laminar flow are important. When you are trying to throttle back, they become less important. Any type of obstruction to the flow will work, as long as it is uniform and repeatable.

      B.B.


    • Mr. Schooley,

      Design straight, shoot straight. :^)

      I would think an issue might be inefficiency corresponding to circuitous airflow, a la the Sterling air rifles.

      /blog/2012/01/sterling-hr-81-177-underlever-air-rifle-part-4/

      Michael


  7. B.B.,

    Thank you for the birthday present!

    Your explanations are effective in painting the picture of what goes into the “power equation” of a PCP. Gunfun1’s and your description of how a do-all PCP (by adjusting power for the task at hand) is perhaps too much of a compromise hits home for me. As my dad would say, “Use the right tool for the job.” While the adjustable wrench is fine for the car glove box, at home have complete sets of both metric and imperial fixed sizes.

    Tone controls, eh? :^) I will use your analogy for each variable affecting all of the other variables, Hi-Fi tone controls, for a somewhat different analogy. I am a lifelong audiophile. My signal path at home (car, I don’t care) is nearly all-analog. (I do have a CD transport, but the DAC has vacuum tubes/valves in the signal path.) Most of what I listen to at home is vinyl or open-reel. There are no integrated circuits or solid-state components. My amplifiers do not even use printed circuit boards but are hand-wired on turret board / tag board a la the photo below (not my pic but just like that).

    When my nephew asked why my Hi-Fi has no tone controls, just a volume control, I used the phrase many audiophiles use, “Tone controls are to make bad sound sound less bad. Good sound is already good.”

    Perhaps power adjusters are like tone controls on a Hi-Fi in the negative, compromise sense.

    Therefore, I take this away: If one wants to hunt (and/or plink) with a PCP, adjust a higher power one to its highest setting and go with that, period. If you are a plinker and paper-puncher only (like me) get a PCP that is low power and go with that, period. What I need is a Diana Model 27 version PCP. Lightweight, accurate, light triggered, many shots with little effort, quiet. An all-day shooter PCP. A restocked/skeleton stock, de-tuned Marauder would work, as would a Fortitude with replacement trigger. Better yet might be a restocked/skeleton stock Challenger or moderated Edge.

    Michael



      • B.B.,

        We are all so predicable :^). Air guns, knives, wristwatches, Hi-Fi, guitars . . . .

        I also collect smoking pipes. I don’t think I could be considered a collector, but I have a fascination with vintage pipe-appropriate lighters. I still have the military helmet (combat and dress) collection, which goes back to The Great War. (I wonder how much — if at all — those have appreciated since I stopped collecting those.)

        Michael


        • Michael,

          Back in the ’80’s, I had some nice pipes. Always 3/4 to full bents. Many Free Hands. I ordered a Meerschaum egg/eagle claw direct from Turkey. Link below. I can’t find anything I like to put in it though. I used a mix of Lane blends back in the day. Finding a shop anymore is about like finding a needle in a haystack. Oh well, just thought that I would share that we have something in common, other than air guns,…. 😉

          https://www.altinokpipes.com/altinok-meerschaum-pipes/churchwarden-pipes/CW1014-meerschaum-churchwarden-claws


          • Chris,

            That is one elegant, sweet looking pipe! I have a meerschaum from Turkey as well, but not that nice. Nice cool, dry smoke.

            I long ago gave up trying to find anything that isn’t online. I try to carefully read the descriptions and read between the lines. “Cool” and “smooth” are code for mild, refreshing probably means slightly biting, and so forth.

            I had a respiratory infection about a year ago that prevented me from smoking a pipe (which I did only on occasion to begin with) for a few months, and I got out of the habit. While I would enjoy smoking a pipe now and again, but frankly, I don’t think about it often. I need to actively start again.

            It’s a great way to relax. I would often have a bowl or two as I plinked off my patio with an air gun or two. The smoke keeps the gnats away, too. A pipe, a cold beer, and an HW 30s! That’s the sweet life.

            Michael.



            • Michael,

              Check out the site if you have not. There is some educational stuff too. As you know, they are not all the same. Meerschaum can come from other countries, but Turkey is considered to be the premium grade. Export of raw material is outlawed. The pics of guys digging the stuff up by hand is utterly amazing and looks to be like it is from some rouge mining operation back in the 1800’s. Wow. Block. Not some compressed powder. Service was impeccable and direct contact with the owner via e-mails was common. The case is a work of art in and of itself.


              • Chris,

                The block meerscaum, which is available in large size and large quantities, is the stuff one should have a pipe made of. The composite ones are probably one-third adhesive/binder. Who knows what chemicals are produced by that when it is exposed to 800 – 900 degrees Fahrenheit?

                The Turkish government banned uncarved meerschaum exports to protect their exponentially growing carving industry, a long term gain and very shrewd move if you ask me.

                And yes, the case-making industry growing right along with it. They are extremely cool in and of themselves, I completely agree.


      • B.B.,

        I almost forgot, I also collect manual portable typewriters, especially models associated with my favorite writers. Most folks don’t know that very often a writer’s style can predict the model(s) of typewriter he or she preferred. And, typically (some noteworthy exceptions) for writing, not office task typing, one chooses a manual portable model, not a standard (desk/office) and/or electric typewriter.

        I also have, then, a dasKeyboard at my computer. If you loved the old IBM keyboards of the early 1980s, you would love the tactile/audible click of the das. No mushy Chiclet keys for me! Hardcore users of the dasKeyboard will sometimes choose their unmarked model — no markings on the keys.

        “SIGHTS? I don’t need no stinking sights! If you can shoot, you don’t need sights.” — Lucky McDaniel (O.K., Just joking, he never said that.)

        Michael



          • Bob,

            Probably not, as I have a Hermes Baby (John Steinbeck’s favorite typer) already, but those are among my favorite small typewriters. Very snappy, and small enough to fit in a small backpack or brief bag.

            Just the same, the phrase “like new” is enticing, I’ll admit.

            Michael


      • B.B.,

        And just look at that lead-dress in the photo I included up above. That’s military-grade layout and work. To an electronics technician that is like a pinup of Betty Grable or Gina Lollobrigida!

        Michael


    • Michael,

      I agree completely – use the right tool for the job…

      That is what I tell my wife when she catches me looking at yet another pellet gun or fishing rod. 🙂

      Think that the Fortitude (with and upgraded trigger) just might be the ideal plinker/hunter.

      Hank


      • Hank,

        I’m not a fisherman, but I have read every single published work by Ernest Hemingway!

        Fishing rods are easy to defend. Deep Sea fishing, surf casting, lake, stream, trawling, fly fishing, heck, even a bamboo pole off of the dock at a small pond. Every type of fishing requires a different rod.

        Michael


        • Michael:
          Very true. Best fishing in Michigan is to drill a hole in the ice and set a jig and tipup then go back into a warm house and wait for the little orange flag to pop. Ice fishing jigs are inexpensive way to start a collection of fishing gear.
          William Schooley


          • William,

            Upper or Lower?

            On the other side of the lake my uncle and cousins all grew up in Rhinelander, WI, and my great uncle lived in Eagle River. I remember visiting when I was a boy and looking out the front window (lakeside, of course) to see if the flag had popped up. Ah, walleye and northerns! Those were the days. I learned how delicious Bluegills caught off the dock with a bamboo pole are, too, although each one is only two mouthfuls.

            Michael


            • Michael
              Those are small Bluegill. Ares average about 8-10 inches around here. And they are tall and thick. You can’t wrap your hand around them and they are easy 2 inches thick or more. I fillet them so you get two nice big peices per fish. I can eat 2 fish which is 4 peices and start fill full. And but of course I don’t stop there. They are just to good. 🙂




      • Chris of England,

        Yes, in some respects, although not to the degree my wife, a retired corporate web designer, has been. I’ve been a PC user since the early 1980s, which in 2018 is a bit of a rarity. This is going to sound strange, but strictly speaking, I’m more of a keyboard snob. I do not collect anything computer-oriented, including keyboards, but I insist that the interfaces between me and those I communicate with are as comfortable and as much to my liking as possible. I also do quite a bit of writing given my profession.

        I cut my teeth on IBM keys, from Selectrics in the 1970s through PC, AT, and XT keyboards in the 1980s. The dasKeyboard has that same “clickety-click” as well as the same feel.

        Michael



          • Chris of England,

            Read my response to Benji-Don and check out the pic of the first personal computer I ever worked on (for about 3 months, when I moved up to an IBM PC). To think I was using BASIC and actually writing code on one of those! Floppy only, 96k!.

            Michael


        • Michael,

          That brings back some memories, our first PC at work, we built on a minicomputer frame and had the DOS code modified to run it. Bill Gates was basically giving it away back then. It had 128 k memory and had two 8 or 9 inch floppy drives. They were very floppy. The interface was a screen and keyboard. If I could help it, I did not use many punch cards after that.

          I got lucky, I had no computer skills when I started working and my work leader told me that I should learn how to use one. So he did most of my work for about six months while I worked on an old Wang 16 k computer. I could run programs and even do some programing. His help and encouragement changed my whole life.

          Don

          Don


          • Don,

            DOS, absolutely. For the first couple years it was 96-128k of RAM, DOS, two 5 1/4 inch floppy discs (the big ones were just a hair before my time), no hard drive, of course no mouse, small monochrome green monitor, and my friend the A: prompt!

            The first PC I worked on was a Commodore SuperPET (96k of RAM), but I quickly moved to an IBM PC with 128k.

            My mother started using mainframe computers as a data entry clerk. The machines filled (and heated) a good sized room and the data storage was on magnetic tape! That would have been roughly 1972.

            Note the SuperPET, below, is one piece, including monitor. It probably weighted 90 pounds.

            Michael


            • Michael,

              Yep, I ment 128 k memory, and the floppy was 8 inches. Had two cups of coffee so brain is a little better. I think going from punch cards and ticker tape to floppy drives, monitors and keyboards was a monster step. Speech is the next one but a large office with people in cubicles talking to their computers will drive you crazy. At least it did for me, but that was when I could still hear.

              Don


  8. Great stuff BB!

    I am part of the “tune to optimum then leave it alone” crowd. There are enough variables with wind, pellets, .etc that adding more by twiddling knobs is not going to help with consistency. 🙂

    Its good to be able to make adjustments but its probably best that most rifles require some disassembly to access them. Great for the knowledgeable user but the average user is better off assuming that the factory knows how to set up their products and leave well-enough alone.

    The FX Crown is something special. It has all of its adjustments (hammer spring; transfer port, regulator) available externally and even has a system that allows swapping the barrel liner for different calibers and even different rifling twist rates. While this might be a tinkerers dream it would be a nightmare to the average shooter where “simple” is best.

    BB, would you consider doing a how-to blog on setting up the hammer spring, transfer port and regulator from scratch? How would someone approach the basic setup to get to the point that they are in the ball-park and are ready to start fine tuning to a specific pellet. Think this would be helpful if someone had gotten too extreme with adjusting settings and now the rifle is totally out of wack.

    Hank


    • Hank,

      Thank you for thinking enough of me that I could write that report. I will think about it, but tuning PCPs is as much an art as it is engineering. But engineers do it all the time, so there has to be common ground. I just have to identify it and then figure out how to write about it.

      B.B.


      • BB

        I am real cautious when changing settings (on anything!) and make notes, take measurements and pictures so I can go back to square-one if I need to. Not everybody does and could easily end up in deep water!

        Just guessing here. Thinking that with PCPs I would choose a regulator setting, set the transfer port full open (if adjustable) and start with a heavy hammer tension and work from there to get into the expected velocity range for that rifle. The tune for efficient use of air, then fine tune for the pellet.

        Might be a fun exercise. I have a Dominator 1250 that just might become a volunteer (victim??) – I would take lots of notes and pictures if I did decide to give it a go. 🙂

        Hmmm. Thing there might be a couple of useful posts on the Weihrauch’s Owners forum.

        Hope you come up with something.

        Hank


        • Hank

          I don’t think jacking up the striker spring would be a good idea . You are operating with a lower pressure with a regulator. You will start slamming the valve hard that way and bottoming it out . Possible damage and erratic operation .
          Determine where the valve is still working right at the new operating pressure. You may find that turning down the striker spring pressure is a better choice.

          tt


          • TT,

            Good point – could be better to start lower and work up.

            This is why I am requesting some sort of guideline or approach to the basic setup of a PCP – might be a handy reference.

            Hank


            • Hank

              From my AA T200…..
              Start with the striker spring set low .
              Adjust up slowly until the velocity spread shrinks as much as possible .
              Stop there .

              FWB 800….
              Adjust up until the velocity tops out and starts going down (valve bounce).
              Back it off a little so it won’t bounce .
              Back it off a little more .
              To adjust for accuracy, only turn it down, never up .

              Talons….
              Turn it up until velocity tops out.
              Turn it down until velocity gets erratic and gets lower.
              Turn it back into the best area.

              S500….
              No striker adjustment .
              Set power adjuster for best accuracy for best pellet .
              stop.

              tt



                • Mildot

                  Between the strangler screw , striker adjustment , and adjusting fill pressure , you can move a T200 around pretty easy.
                  I had 14 ft-lb out of mine with 8.4 Exacts. All I had to do was back out the strangler and start with a lower fill pressure. Did not have to touch the striker adjustment.

                  tt


                  • TT
                    Same here on the Marauder rifle, pistol and 1720T.

                    I usually set my striker stroke at full stroke and adjust the striker spring pressure up or down.

                    I found if I have the striker stroke screw adjusted out for less stroke the striker stays closer to the valve and it’s more apt to have valve bounce. And worse. Like the striker resting against the valve and causing a slow leak down. And in some cases depending on how heavy the striker spring is set a rapid leak down from the valve. And on both instances that leak down occurs from out of the barrel.


                  • TT
                    Those are nice on your gun.

                    My main thing was to let people know that adjusting the striker spring heavy and having the stroke adjusted short on the Marauder type striker and spring adjustments. You can run into leak down problems by having the striker resting on the valve stem.



                • Hank

                  These were a bit abbreviated, and would require a bit of fine tuning but they get you in the ball park .
                  Someone else may have a bit different methods. As long as it works.

                  tt


  9. B.B.,

    I suppose one could use a Sheridan Blue Streak and write down the different P.O.I. for each number of strokes. :^) If it were a Steroided one, there would even be 2-stroke all the way up to 12 stroke or more power settings!

    On that subject, I think the next to big developments in airgunning will be multi-shot multi-pump pneumatics and powerful single stroke pnuematics.

    Michael


    • Michael,

      I learned to hunt with a Crosman 101 – 8 pumps and one shot. You don’t know how many times I wished I had a quick follow-up shot.

      The FX Independence is such a rifle but at a very high price point. I’ll get one right after I win a lottery. 🙂

      Hank


    • Michael
      I hope that happens. I keep saying over and over I would like a modern multi-pump that gets one shot per pump. Not a self contained pcp. In other words I want to control velocity by how many pumps I put in the gun.

      And obviously that’s nothing new. The new that I would like would be a repeater magazine breech that also accepts a single shot tray. A fully shrouded barrel and a fully adjustable 2 stage trigger.

      What does that sound like to you? Resemble a Marauder rifle by chance. 🙂



  10. Michael, I meant to say, with respect to your LVG, that it seems ripe for a tune. Perhaps that would eliminate some of the rough behavior. When I first received my B30, parts would periodically drop off. But after it was tuned by the mysterious Rich from Mich, who seems to have completely disappeared from the airgun world, it shoots like a champ.

    Though I don’t shoot pcps, all of today’s blog was eerily familiar to my experience with my M1 Garand. But after all, both firearms and airguns are powered by compressed gas, so maybe it’s not surprising that similarities would appear. To recap, my Garand has a customized gas system. A set screw in the gas tube under the muzzle moves back and forth by means of a hex key, and the various positions of the screw change the volume of gas that moves the op rod to cycle the bolt. The idea is to adjust the volume so that the op rod starts moving right after the bullet exits the muzzle so as not to disturb your shot. I had the gun tuned permanently (as I thought) by the inventor for a specific load. However, the rifle went out of adjustment and the inventor dropped out of touch. Without the adjustment, I found that the rifle not only didn’t optimize accuracy, but it wouldn’t even work properly and jammed often. In the last 10 years, I’ve had the devil’s own time diagnosing the problem and then finding the right gas setting. To complicate things, I have a large quantity of two different loads on hand to adjust for.

    Last weekend, I charged into the breach again, and I think I might have the answer!! For Greek surplus, a set screw depth of .395 inches works perfectly. This is what I have searched for for years. Lock those numbers in the vault with the secret formula for Coca-Cola. It happened like this. With my first clip at .410, I had a couple jams. Did I rage, scream, and tear my hair? Not a bit of it. In the “cool Marine way,” I simply dialed it back to .395. I felt like Sergeant John Basilone on Guadalcanal rolling around and repairing his machine guns in the middle of nighttime banzai attacks–but 1/8th the actual size. Anyway, it worked. Not only did I not get jams, but the gun felt happy. It’s said that you can see elephants smiling, and I could feel the gun smiling. It truly felt like a symphony in the hands. I understand now why Mikhail Kalashnikov considered John Garand (not John Browning, surprisingly enough) as the ultimate gun designer of all time. I didn’t quite find the right setting for my handload, but I am closing in. Loading only full instead of partial clips eliminated another source of jamming.

    Now that I have the key setting information, I have to figure out how to maintain it which is another similarity to pcp adjustment. It’s distracting enough to adjust the screw between my two different loads. But it has become clear that the screw moves in response to shots, and continuous checking and readjusting is a hassle. If I had one load, I could loctite the screw in but not with two. One other option I’ve heard about from another gunsmith is removing the set screw, placing it upright on a hard surface and whacking it with a hammer! This is supposed to bend some of the threads and hold it in place tighter. After finally getting the rifle to work properly, I’m not about to go hitting it with a hammer. But I am keeping this in mind. Maybe I could buy an identical screw and experiment with that one…

    Matt61


  11. O.K., I was at work while you guys were talking about this all day, so I’m late to the party. I recently chronographed my stock (no pun intended) Gen 2 Maurader. First, when my hand pump said 3,000 PSI the gauge on the gun said about 3,200 PSI. Which am I to believe? Anyway, that’s where I started. I shot six 10-shot strings:

    Ave. Ext. Sprd. Std Deviation
    891. 10. 4
    891. 11. 4
    897. 10. 2
    891. 14. 4
    881. 26. 8
    850. 40. 13

    So, the factory settings in this case seem to provide a pretty flat curve for almost the whole first five strings. Only in the sixth string does it all start to come apart and by that time the PSI was down to 1800 PSI (indicated on the gun’s gauge).

    So, here’s the question: Would I gain much by putting a regulator on it or some such other “tuning” techniques? It seems about as consistent as some of my .22 spring piston guns that provide pretty good accuracy with those similar numbers?

    Motorman
    St. Louis, MO


    • Motorman
      So you got 60 shots out of your .22 Marauder. And 50 before it started falling off.

      You better leave that gun alone and not touch a thing. Well that’s if it’s accurate.


    • Motorman,

      If that is the way you like it I agree with GF1 leave it alone. I have four small gauges and they are all different. The one on my Marauder reads higher than the rest. When my fill tank gauge reads 3000 the Marauder reads 3400. your two gauges are about as good as it gets with the small gauges. As long as you use the same gauge each time you should get the same results.

      I am shooting heavier pellets a little faster so I wont get that many shots before I start falling of the power curve.

      Sounds like a great tune out of the box. So did you just get this Marauder? If so they are supposed to be putting the new barrels out now. So I can’t wait to hear how it is for accuracy. The Hobbies should be good at that velocity.

      Don




    • Participant
      They say it’s not. The new one they just released that is. The one that’s been available through the Crosman custom shop for a while was originally suppose to be a adjustable regulator but I believe it is not also.


  12. GF1
    Thanks for the info, it is good to know. I am watching for one of the new batch of low cost PCP’s to have an adjustable regulator pressure. I would like to get one that has the adjustment range right out of the box that the Maximus you built has. Not a need, just on the wish list for now.
    Gerald


    • Gerald
      I’m guessing that if you took the fill fitting out of the Fortitude the regulator will come out. And I bet it is adjustable.

      But no way to know for sure unless we have one in hand to take apart and see I’m thinking.


  13. GF1
    I will watch some of the chat forms to see if that comes up. I think that most of the new items at shot show will not be out before the snow is gone here. I can wait and watch.
    Gerald


    • Gerald
      I see that they moved the available date up to 2/15/2018 for the Fortitude. It was like 3/29/2018. So we just might know more about it sooner than you think. I know I’m getting one in .177 caliber with out a doubt.



  14. Excellent discussion here with one of the Crosman product managers with a lot about PCP tuning.
    The maurauder regulator is not intended for user adjustment but not impossible.
    They are claiming their new barrels are as accurate as the LW option.
    Lots on the Fortitude. Not sure how they will keep selling Marauders.

    https://www.youtube.com/watch?v=6tBKEc55R78&t=8s

    Kinda funny, Daystate insisted for a very long time that their guns are tuned well enough without a regulator. This year they are adding a regulator to the Wolverine at least. I’m not sure it that’s just jumping on a bandwagon or if they really changed their thinking. The regulated version does have an impressive shot count. Perhaps I will regret not waiting, but I suppose there will always be the next model.

    Michael

    In my 20s I’d hang out at Audio Ark in Edmonton Alberta, Canada’s highest end audio seller. I dreamed of one day owning pure sound. Now when I have enough purchasing power to consider it I’ve discovered there are frequencies my ears completely ignore, so I’m not even tempted to spend the money. Just a slightly sad irony. Not that sad though when there are PCPs that don’t require good hearing.



  15. BB,

    I was wondering about the Marauder Field and Target. I understand that it is a regulated PCP, and was wondering if it could still be tuned in the same way as the older versions of this rifle

    Also was wondering if when the regulator fails if the gun would still function as a non-regulated
    PCP?


    • Airfun,

      Welcome to the blog!

      That is a very good question! I think there have to be some differences because of the regulator, but I’ll have toi wait and see.

      Yes, if a reg fails the gun reverts to being like an unregulated gun. At least that is my experience.

      You can always post your questions on the current blog page. We don’t worry about staying on topic.

      B.B.


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