Diana Bandit PCP air pistol: Part 2

by Tom Gaylord
Writing as B.B. PelletierDiana Bandit

Diana Bandit precharged pneumatic air pistol.

Part 1

This report covers:

  • 200 Bar fill
  • The test
  • RWS Hobby
  • Discussion
  • Second string
  • Discussion 2
  • Chronograph
  • Tyler’s video
  • What does that leave?
  • Back to testing — JSB RS
  • Heavy pellet — Baracuda
  • Discussion 3
  • Discharge sound
  • Trigger pull
  • Summary

Today is velocity day for the .22 caliber Diana Bandit PCP air pistol. Let’s get to it.

200 Bar fill

In the manual Diana emphasizes stopping the fill at 200 bar, which is 2,900 psi, so that’s what I did. The reservoir is 50 CC so I filled it first from the Nomad II compressor. The pistol was sitting at 180 bar, according to its onboard gauge, and it took just a couple minutes to fill.

The test

I’m going to test three pellets — light, medium and heavy. I’ll start with the light one.

RWS Hobby

The first pellet I tested was the 11.9-grain RWS Hobby. At 11.9 grains they are lightweight, but also pure lead that is accurate in many airgun barrels. Instead of the average let me show you the string.

Shot…Velocity
1……….711
2……….716
3……….729
4……….755
5……….729
6……….723
7……….730
8……….did not register
9……….674
10………656
11………644
12………641
13………629

Discussion

That’s a very peaked power curve and there is no real average that represents anything. It tells me that the powerplant is not set up for consistency; it’s set for power. The spread over 13 shots is 126 f.p.s. The gun will probably group well at 10 meters, but at 25 yards there will most likely be some vertical stringing. And 7 or 8 shots will be it for the gun as it is.

I was intrigued by the first string because I know that a lot of shooters will be counting on the Bandit, so I decided to run a second string of Hobbys and to use a different fill device. My 98-cubic-foot carbon fiber tank has a very accurate gauge on it, so let’s see what that will give us. Again, I filled to 200 bar, but this time I watched the tank gauge, and did not rely on the compressor’s shutoff gauge.

Second string

I think the onboard gauge registered 10 bar more (210 bar) after this fill, because it filled the pistol so fast I wasn’t able to shut off the valve quick enough. The tank gauge did settle back to 200 bar, but the gun seems to have taken on more air. Same Hobby pellet.

Shot…Velocity
1……….632
2……….655
3……….663
4……….680
5……….687
6……….701
7……….715
8……….719
9……….723
10………720
11………710
12………667
13………648

Discussion 2

This string tells me a lot more about the pistol. The powerplant is definitely not adjusted to shoot with consistency. It does not have a balanced valve. Given how low this string started I expected to see about 20 shots, but instead it peaked at 723 f.p.s. — a full 26 f.p.s. slower than the high point in the first string. And this curve is just as steep as the first one — it’s just in a different place.

There is no real average again. The extreme spread is 91 f.p.s. If we take 680 as a representative velocity the muzzle energy for the Hobby pellet is 12.22 foot pounds.

At this point I started looking for the magic screw that adjusts the hammer spring tension lower. Because that’s what a string like this tells me — the hammer is holding the firing valve open too long. Of course you can always increase the valve spring tension, but that requires disassembly. There is often an adjustment on the rear of the receiver of a gun that allows you to back off on the hammer spring.

I looked and there is a screw in the back of the pistol grip, but it holds the grip to the barreled action. I removed the grip and could find no hammer spring adjustment screw.

Chronograph

It’s obvious that you need a chronograph to run tests like these. Either that or shoot at long distances and watch the shape of the groups as they grow.

Tyler’s video

Not wanting to be a complete fool and have one of you readers tell me that Tyler Patner shows how to adjust the hammer spring in his Insyder video, I now watched his video. Son of a gun if he didn’t get similar results! He tested a .177 and a .22 side-by-side and the .177 did get more shots per fill.

What does that leave?

It’s obvious — even to a dinosaur like me. The Bandit needs a regulator. And Pyramyd Air sells one! The Diana regulator for Stormrider and Bandit is the one they sell. I’m sure there are other aftermarket regs out there, as well. The Diana reg adds $90 to the cost of the gun, but you don’t have to buy it when you buy the pistol. You can get the pistol and learn to enjoy it, then pop for the reg down the road. One Pyramyd Air customer put one on his .22-caliber Bandit and got a significant increase in consistent shots. Once you find the magic pellet, that consistency increases the effective range of your pistol, so there is motivation for adding one.

Back to testing — JSB RS

Okay, there is a lot to consider, but I will resume the velocity test with the JSB Exact RS that I’m using as a medium-weight pellet. Again I filled to 200 bar.

Shot…Velocity
1……….634
2……….652
3……….660
4……….671
5……….691
6……….695
7……….703
8……….696
9……….679
10………643
11………623
12………608
13………595 — 145 bar remaining

Once again we see a peaked curve with no real average. The total spread for 13 shots was 108 f.p.s. If we take 680 as a representative velocity the pellet generated 13.79 foot pounds at the muzzle.

Heavy pellet — Baracuda

The final pellet I tested was the Baracuda with a 5.50mm head. They weigh 21.14-grains and gave the following shot string.

Shot…Velocity
1……….528
2……….540
3……….550
4……….557
5……….562
6……….569
7……….563
8……….549
9……….510
10………502
11………492
12………479
13………470 — 145 bar remaining

This 13-shot string gave a spread of 99 f.p.s., but look at the first 8 shots. The spread there is just 41 f.p.s. That looks useable! And, if I take 550 f.p.s. as a representative velocity, this pellet generates 14.20 foot-pounds at the muzzle.

Discussion 3

If this pistol were regulated to around 160-175 bar I think there would be more good shots per fill. And it would be a roughly 14 foot-pound air pistol. Of course we need to see what kind of accuracy we get, but that’s in Tyler’s video as well and I will test this one with different pellets than he did.

Discharge sound

I have to say the discharge sound is quite low. Give the power I expected it to be louder. I think this pistol might be okay for a large back yard.

Trigger pull

The two stage trigger takes 14 ounces for stage one and exactly 3 pounds for stage two. It’s very crisp and I should be able to do good work with it. I really don’t want to adjust it because the adjustment regulates the amount of sear contact area, and I would rather be safe than sorry.

Summary

That’s all for this report, but the Bandit pistol looks like a project that’s looming. I first want to test accuracy with both a dot sight and then a scope. I’m thinking of how I will do that. Maybe the dot at 10 meters and that will also help me find a best pellet. Then back to 25 yards with a scope, once the best pellet has surfaced. At any rate, it looks like a lot more fun is in store!

118 thoughts on “Diana Bandit PCP air pistol: Part 2


  1. BB,

    That’s OK. It showed up.

    This thing would most definitely benefit from a regulator. Maybe. If you are just shooting feral soda cans, a little vertical stringing will not likely be noticed.


  2. BB,

    A work in progress to be sure. It does have the space age style thing going for it,.. if that is your thing. My initial thought was,… “How did this thing ever make it out the door?”. Then I thought back to my .22 Maximus getting a 100 fps spread over 30 shots,.. in stock form. Once regulated, the highest was 784 and the lowest was 773. The last shot (30) was within 2 fps of the first shot. Any shot to shot spread was very minimal and if it did peak,.. it was around shot 10 or so. I did back off the fill to 2800 instead of the tested 3000, but I have not ran it over a chrony again to verify anything. 30 shots with that spread is more than good enough for me.

    So given the size ratio(s) between the two, I guess it makes sense. It would also appear that a PCP pistol would almost call for a regulator right out of the design gate due to the much smaller air cylinder.

    Good Day to you and to all,……… Chris

    Edit: I will add,… slow to recover regulators are (completely unacceptable) for any gun,.. be it a pistol or a rifle. Especially if it is has a magazine (repeater). I believe we have seen a few of those here in recent past.





          • RR,

            Well worth it if the Maximus is what you are going for. Yes,… It has to be removed to reset it. I used a long piece of garden twist tie (think bread tie) to pull it out. A wood dowel to shove it in. Maybe 4-5 times. $115 plus $11.53 shipping from a (just now) look up,.. from A of A. No regrets thus far. I did use a piece of fuel line hose to add resistance to the screw so as to deter any movement. In the end,.. it is a terrific, lightweight shooter! I would look further into the Fortitude,… before you pull the trigger on something if it were me. I have not.

            Chris


            • Chris,

              Though the Fortitude has much to offer, I cannot do with it what I can with the Maximus. The only real advantage it has is the magazine, which I could care less about.

              The truth is the Fortitude has been around for many years. I was not interested in it then, I am not really interested in it now.



                • Chris,

                  That has yet to be seen. I know of enlarged transfer ports, adjustable spring,two stage sear, silencer adapter, LW barrel …

                  The truth is you are only limited by your imagination and wallet.



  3. B.B.

    Interesting pistol – I was surprised at the price.

    Think that the large ES is likely due to the “power” setup of the hammer spring and that each shot takes a (relatively) large gulp out of the working pressure of the smallish reservoir.

    The pistol is available locally ($229.00) and would probably be much happier (shot count wise) at the 495 fps maximum limit here in Canada.

    Tyler mentions that the grip is large. Diana probably did that on purpose so that there is enough wood that the grip can be rasped/sanded to a custom fit.

    Hank


  4. B.B.
    Your shot strings resemble the numbers my Bandit produced. I felt that with a bit lower fill pressure there is 7-10 good shots per fill. I bought the regulator to hopefully get two magazines (14 shots) of consistent shots per fill. I am not rushing to get the reg. in as I don’t have a winter range set up.
    Gerald


  5. BB,

    From the looks of the gun and from Tyler’s comments, this gun is very similar to the Diana Chaser. I have the Chaser in the .177 rifle/pistol combo that, of course, is powered by CO2, so it isn’t exactly identical to the gun you’re testing, but I may still be able to offer a suggestion on your accuracy testing.

    Despite what Tyler says in his video, the suppressor screwed right off of my rifle barrel and onto my pistol barrel and by making that switch they both shot more accurately at the 13 yards of my basement range. That improvement held true for 24 different pellets in the pistol and more than that in the rifle, although the biggest improvements came in the pistol.

    I think that the improvement may be coming from either better harmonics or the suppressor is effecting the air flow from the muzzle of the guns. I don’t know if the barrel on your pistol is the same length as mine but I know that my pistol is shooting a 7 grain wadcutter at around 500fps, much slower than your gun. The CO2 power plant is probable responsible for that more than anything. For that reason this may not give the same result with your gun, but I thought I would mention it in case your gun wasn’t accurate when you test. Screwing off the suppressor is a pretty easy mod if it improves accuracy, as it did on my rifle.

    I would also mention that on my stormrider, which I think is similar to this platform, I was able to solder closed the removable transfer port and redrill it to a smaller size and that lowered my velocity some and gave a flatter power curve and larger shot count, as well.

    Half



      • BB,

        Daystate and Air Guns of Arizona have been dealing with the same thing. Some are sent glued on and others will come right off. I think there is still some confusion as to what is allowed and what you can get by with. As I recall last,…. they still needed to be permanently affixed to be “official”. I will let you guess what mine do. 😉

        Chris


      • BB,

        Although I didn’t require it on my gun, I’m pretty sure your suppressor would release with a hair dryer. I understand if you don’t want to fool with it. I just wanted to make you and others aware that on the Chaser the suppressor changed the accuracy by 60% in some cases and that it was easy to try.

        Half


        • Half,

          On the Maximus, Hunter version,… the 1/2-20 muzzle end would (not) come off. I was playing with barrel bands at the time and was seeking a removal,… as I recall. Industrial heat gun. Non- Chinese cheap glue,… I guess.

          By the way,… a cheap $5 screw on baffle unit proved the best of all. Better than a $35 air stripper and better than the stock muzzle cap. I do believe that harmonics factored in,… but have nothing to prove that theory.

          Chris


  6. BB
    I wonder if the suppressor lets the propelling air actually bypass the pellet and then work against it in the next chamber? Seams like it would take a bit of serious engineering to calculate the effect the design may have on the pellet as well as the sound, and at various PSI.
    One size fits all may only work for the sound and have various effects on the pellet design. Especially a wad cutter.
    Bob M



  7. Folks,
    In searching for a good tune for this pistol, which came with a powerfull single mag tune,
    I too sealed up its transfer port with JB weld and C.A. glue and redrilled a smaller hole.
    That helped flatten out the sting.
    I opened up the hole back when I got the reg.
    With a regulator and a few other mods, I could get almost two full mags at 750 fps with
    JSB RS. Of course, while trying to improve that tune, I cut off too many spring coils, ruined that spring.
    As a result of not having a dplicate spring around, the next closest spring would only get 620 fps,
    but it was a consistant regulated velocity, so now I have nearly 3 full mags at 620 fps, not the 750 I wanted.
    I tryed shimming the new spring to get the velocity up, but it made no change. So I will overrhaul it again and see if my reg set point has shifted from the hammer beating on the valve body. And I will try Halfsteps suggestion to increase the valve poppet spring rate some.My .177 is a one hole gun, so while it not stock, I think it has a great barrel. This is the crucial part: while this all happens, i use the P1 and the R10, which are always ready to go, and very accurate to be sure.
    Santa’s bringing a Synergis and a micro dot sight for the P1. I may keep the Synergis, or my brother might get it,
    well see.
    Happy holidays everybody!
    Rob


  8. Chris USA ,

    I agree 100% on the slow regulator recovery . This happens in high end guns also . Slow reg recovery is bad in a gun that started life as a conventional dump valve as they need 50 bar just to seat . A good trick is to put pellgunoil or air tool oil on the fill assy. and fill the gun , the oil laden ed air will free a sticking tappet. I see this allot . This is safe as pellgunoil flashpoint is 350 degrees F , same with airtool oil .


    • Gene,

      I put a drop or two of silicone air chamber on my fill nipples every other fill or so. No issues thus far. I do that with the .25 Red Wolf (electronically regulated), the unregulated .25 M-rod and the now regulated (by me) .22 Maximus.

      We (the blog posters) also had a discussion awhile back on cycling PCP charging equipment from time to time. At least cycle it, if not actually use it. I shoot my PCP’s in the Winter too,… if only for 5 or so shots at an indoor target box at least once a month. While it seems like common sense,… I do not recall that advice ever being widely touted. Maybe a good PA educational video topic idea?

      Anyone with a large collection that also can not shoot that much, could spend the better part of a day just doing “maintenance” cycles.

      Good Day,………. Chris


      • Chris,
        Regarding “cycling PCP charging equipment from time to time”, I have read on forums that the cheaper compressors with Chinese O-rings need to be cycled often or the O-rings will dry out and leaks will occur. Here is a YouTube video by a fellow who lives not far from me. He is talking about the expensive Omega compressor, but it’s applicable to other compressors as well. His channel is Airgun Reviews & Hunting.
        https://www.youtube.com/watch?v=ON0UNFr8UQw
        Geo
        Hey! We are back to the user names being shown again 🙂


        • Geo,

          Thank you for the link. You are a literal gold mine of link knowledge,.. as always. 😉

          Bottom line guys,…. use them or at least cycle them,… or be ready to spend some down time fixing them. I would think also,.. like I said to Gene,.. that an occasional cycle of air guns would also be a good thing to do. Hand air pumps as well,.. I would presume.

          Chris


          • You are very welcome. Ken’s YouTube channel “Airgun Reviews & Hunting” is pretty new and he does not have the video thing all figured out yet. He’s not my favorite for reviews but has some interesting stuff on occasion.


            • Geo,

              Well,.. he did seem pretty “relaxed”,… or “tired”,…. or maybe sipping a few along the way? Hey,… I very much appreciate that he took his time and effort to put it there for the rest of us to benefit from. Hat’s off to him!

              Being around here only a few short years,… I can remember some of the “You Tuber’s” just like him. Now,…. they are jet setting to the big boy events and even competing. Hard, long OT work can pay. Of course,… having a good bit of good looks, a good bit of humor and some tech skills can not hurt either. The first two are a slam dunk for me! 😉 The tech stuff I am still working on. 🙁

              LOL!,………… 🙂 Chris

              PS,… on the credit freeze thing,… OK,… I get it. Mom and Dad use their credit cards for about everything. Payed off every month. In doing so,… you build points and get money back. 10% back is like 10% off whatever you bought even if it was full price at the time. Something to think about for anyone that may be looking to stretch a penny into a nickle. Your approach sounds solid,… but maybe not applicable to everyone. Plus,.. I do believe that credit cards offer additional purchase/problem/refund benefits that a straight up debit card transaction might not offer.


              • Chris,
                We also use credit cards for most of our purchases, and we too pay them off every month. They don’t like me much as I never pay interest. It’s called OPM, using other people’s money. You are absolutely correct about credit cards offering added purchase protection, and in some cases, extended warranties. I recommend never using a debit card because they are tied to your checking account. If they are compromised the money is taken from the checking account, and it can take a while for the bank to resolve and make your money available again. If the credit card it compromised it’s not a problem for you, but the credit card company. You are not responsible for any unauthorized charges. I always have two cards in case one has to be deactivated. It’s happened a few times, and it’s always from someone overseas. We like the cash rewards cards that return 3%-4% on purchases. My Costco card returns 4% on gas. That’s like $.10 a gallon, in addition to being $.20 or more a gallon cheaper than most other stations.
                Hey, did you get the RAV4 repaired?
                Geo


                • Geo,

                  Yes on the Rav4. $800.00+ drive shaft as the universal joint(s) are not replaceable. Feel free to explain that to me. The rear one was at fault. 1 of the two axis’ had become very tight. Like a 20 minute swap out at the local garage. I did throw in an 18 pack of bottled Stella (beer) for the mechanic as they do not normally do repairs on a Sat.. Add $24. It was “subtly” hinted that the Stella “might” be a good incentive on the day before diagnosis. He was happy and so was I. Still,… ouch! 🙁

                  On bargains,… I can remember more than one time when Mom got stuff for free and/or money credited on an item back in the coupon clipping days. A savvy pair they are!

                  Chris


  9. Guess I am Benji-Don again, glad that was fixed, my memory is bad so I did not want to relearn names.

    I have been looking at a used bandit for a while, based on the review so far I will wait for the rest of the review to decide if I want it.

    I have the Chaser pistol/carbine kit like Halfstep and enjoy it a lot. Plenty of shots and very accurate with a good price.

    Don



      • BB,

        Thank you to the “Pyramid IT folks” for that and all the work they do in keeping out the “bad guys”.

        Is there anything that we as posters can do to help qwell? Or,…not do?

        Chris



      • That is great, I remember the time before we had IT, it was DIY. In the beginning of IT it was very frustrating because we built all the software and put the hardware together for our specific purpose we knew what happened inside, IT didn’t. That is no longer an effective process in general with all the multipurpose hardware and software available and the corporate connectivity requiring uniformity. Good IT is now critical to compete. From what I can see from a distance PA has a great IT department that is actually listening to the customers.

        Don


        • Yes, I agree that Pyramyd Air’s IT department is doing a good job staying on top of the issues.
          IT is a very broad term nowadays. When I was still working, I found the IT people to be more of a hindrance to me than a help. They got in my way of getting things done and wanted to micro manage my computer settings, which was aggravating.
          Also, I have found IT people to be very tech specific. For example, my son went to college and graduated with a degree in information technology. He has no idea how to repair a computer. I had to show him how to install a new video card in his computer and configure it. IT people do not repair things in general because it is not timely. If a system fails, they just replace it with another unit and move on.
          Here’s another thing, my son who is now 40 years of age, has not been able to find a job in IT. He says you have to know someone, or have years of experience. He’s working in the stock room at Meijer grocery store. Pretty sad with the expense of achieving a four year degree in IT.
          Geo


          • Geo,

            Other fields are the same way. The auto/diesel repair field can be the same way. Be VERY careful when going “to the line” of taking on debt for education. Intern work in summers can be beneficial. Make contacts. Top of class can be a big benefit and may get a job referral from the “inside” of the educational institution if new to the job market. No doubt,… employers have their “feelers” out for a “hot shot”. I do however see companies offering continued/specialized education to (existing) employees. Best wishes on him landing something in the future.

            Chris


          • Geo791,

            My son got a undergrad degree in Business and Economics and a minor in IT.
            He has as a CIO hired a number of IT graduates and almost always finds he needs to send them to school for Certifications on particular software, firmware and hardware systems. He can do some of the teaching In-house but that costs the company more than sending them to the supplying companies training centers. He himself is constantly doing updates to his Certifications and knowledge. Just think of the information industries retail mindset. They have the same constant $$$$$ flow in business plan for the IT folks that use, fix, sell and train with it!

            He should try to learn the Meijer IT folks or the folks that service their data systems.

            shootski


            • Shootski,

              Well said. An elderly gentleman once relayed to me a story of his son. Started by slinging pizza at Dominos. A few years later he was a 3 state manager. So yea,… do not overlook where you are currently at. Life gives you lemons?,… make lemonade. Better yet,…. lemon cello (sp?),.. which I have yet to try,.. or make. On the short list! 😉

              Chris


              • Here’s a twist on that story. A friend of our family graduated with a degree in Chemical engineering. Guess what he ended up doing? He went into the pizza making business and ended up with several pizza places. He never worked a day in his chosen field but said that the education helped him in the pizza business.


            • He did apply for an IT opening at Meijer but they wanted to cut his hours and wanted him to work for less money. So he didn’t go for it.
              Many companies are farming out their IT to outside sources. I saw that happen at Parker Hannifin where I worked. There wasn’t much job security in IT there.
              Also, many companies like to hire IT people with limited knowledge with no preconceived ideas. Then they can train them to do things the way they want them done.


              • Geo791,

                It sounds like the HR Department!

                If your son can somehow avoid the “Human Resources” DIS-partment (intentional spelling) he will be far better off. They are the Bain of job seekers as well as the people who want and need to hire good people.

                I will say this unless someone is in charge they are usually required to follow the leadership’s game plan. If you are lucky enough to have a smart leader that allows constructive comment before the execution phase that is the place to work. Or he needs to figure out how to become self-employed.

                shootski



  10. B.B.,

    I come to you with a problem related with filling the Marauders with air.
    I started off with the hand pump and all went well.
    Then I had a problem, but it seemed to clear.
    As best I can tell the hand pump is fine.
    The Foster connection is not leaking.
    Pressure appears to be building up in the hose.
    A vacuum is created and it is difficult to pull the hose handle up; in fact it is sucked back downward.
    I can’t fill either rifle.
    I read about the dirt filter behind the male foster fitting on the rifles.
    Could they be the reason I cannot pump air into the tube?I
    Can filters be purchased and replaced?
    Is this something a user can deal with?

    I did have a pleasant session with the .177, emptying 4 magazines. I had hoped to tell you about it.

    I am tempted to yell, “CHOCOLATE”, but that would only make sense to those who remember the Smothers brothers skit.

    ~ken



      • Mike,

        “Chocolate”,…..???? Not that I eat that much of the stuff,…. but I will have to watch it while shooting! 😉

        Chris ( I did look at it and found nothing mentioning the avoidance of combining confectionaries and shooting.) 🙂 A brew or two,… or more,…. well,.. that is a different story.



          • Mike,

            Well,…you never know about Chinese to English translations,… so I took you with just the minimal amount of “salt”. Smothers Brothers?,…. I do remember. However,… at that particular stage in my youthful existence,… I am pretty sure that we,…. (as in,.. the kids) were strongly discouraged/forbidden from watching such cheeky humor! 😉

            Chris


          • Mike,

            Amazing what we can remember. I was in junior high. I was spending the weekend at a friend’s house. He played the Smothers Brothers for me and some Singing Nun songs.

            He is one person I have not been able to locate, which is unusual. I will still try periodically, though.

            ~ken


            • I remember the Smothers Brothers show well. We even saw them in Chelsea MI several years ago. Chelsea has (had) a very large boat on the river. It was permanently docked and they had entertainment on it once a year. They called it The Showboat. Tommy even did the yo-yo man bit. They did a lot of political satire (nothing as excessive as today) and the government was always trying to censor them. I remember the chocolate joke too. We loved them.
              Geo


              • Geo791,

                Wow! Glad you got to see them in person. They had difficulty with the network. Almost everyone did. When Johnny Cash sang Sunday Morning Coming Down on his television show, he was told to change the word “stoned” to “home”. However, Kris Kristofferson was sitting in the front row that evening. Not only did Cash sing, “Wishing Lord, that I was stoned”, he accented the word “stoned”. When the Rolling Stones were on the Ed Sullivan show they were instructor to change the word “night” to “day” when they sang, “Let’s spend the night together”. I am not going to take a side in this. Conflict is inevitable. Still, I think it is great you got to get on “The Showboat”.

                ~ken




      • Kenholmz,

        Ken I’m going to answer them one at a time and give you % probabilities for each:

        “As best I can tell the hand pump is fine.

        No it isn’t. 97%

        The Foster connection is not leaking.

        99.9% it isn’t.

        Pressure appears to be building up in the hose.

        On one part of the pump stroke 99.999% on the other 0.1%.

        A vacuum is created and it is difficult to pull the hose handle up; in fact it is sucked back downward.

        99.999% correct.

        I can’t fill either rifle.

        Tells you it is probably NOT the sintered filter behind the male Foster fill fitting 99.999999%

        I read about the dirt filter behind the male foster fitting on the rifles.

        You are correct 100% if the assembler remembered to include it? But NOT the problem.

        Could they be the reason I cannot pump air into the tube?I

        See above items!

        Can filters be purchased and replaced?

        They can 100% from Crosman parts if in stock.

        Is this something a user can deal with?”

        Probably. Pump needs to be fixed 97.0%.
        Why did this happen? New pump? If so assembly problem check with Crosman [pump manufacturer (s)] for assembly error rate. May be sent to them or seller for repair exchange. Used pump? Either previous owner (or you) likely allowed the pump to get too hot while enthusiastically pumping up the Marauders. You need to bleed the condensate valve often if you are in a normal humid house or area; less often if in dry heated house or high dessert area. No more than 50 pumps, bleed and take a break to cool the pump and you. If the pump outside (shaft cylinder) is warm the internals are much hotter! Don’t burn the rubber/synthetic check valves and O-Rings in the pump!

        A bummer!

        shootski



          • B.B.,

            Yes it certainly is! I lived a few more down the coast in C.C. for a number of months and it was always HUMID! I guessed on all the rest of the advice ; )

            Could you house a rediculsly heavy pellet for a pistol in one of your accuracy tests please? It is an unregulated PCP.

            Thanks to you and the PA IT department for the signin fix.

            shootski


          • B.B.

            I have a lot of information, here, thanks to knowledgeable readers who share their knowledge. Your reports and your readers have been the best since I discovered the blog in the fall of 2011.

            I have good news. Jerry has purchased a better compressor and is offering his other at a price I can’t refuse.

            I still want to have a working hand pump.

            Thank you,
            ~ken



        • Shootski,

          It was, indeed, the pump and the solution was simple. Only had to remove the main tube from the base and fix the “check valve”. The o-ring had slipped off. It looked good so I replaced it. I was back in business in only a few minutes (well, a few minutes to do what took a while for me to understand).

          ~ken



        • Ken,

          I saw where you will be getting a compressor at a price you cannot refuse. Good deal.

          And you want a hand pump, lots of options out there. Geo791 says his 85 dollar pump works fine for him, I have this one and it works well https://www.pyramydair.com/s/a/Air_Venturi_G7S_Hand_Pump_4500_PSI/7926 a bit more money but what the heck.

          Many options, and that makes your current pump the learning platform, open it up and see what makes it pump. Best way to learn about it I think.

          Mike


          • Mike,

            Thanks. I have learned something. Once I understood, the current fix proved to be simple enough. It was the “check valve”. The o-ring slipped off at some point. I will post photo in main section of latest blog.

            ~ken



            • Ken,
              B.B. stated that one of the major points of failure in hand pumps is caused by disassembly. When he worked at Air Force he saw several occurrences. With a little mechanical ability, and some proper instruction, I see no reason why rebuilding a hand pump would be difficult. If one can disassemble and airgun, they should surely be able to disassemble a hand pump, I would think. Of course, there are those that know just enough to be dangerous 😉
              Geo


              • Geo791,

                I made it to 69 at the beginning of the month. I have been fortunate (numerous close calls; sometimes my own fault), so I try to get information and have a plan, starting simply and digging deeper only if necessary.

                ~ken



    • Ken,

      No answers for you Bud other than to hang in there! You (will) get it all sorted out right here. Suction on upstroke would indicate an incoming air flow issue,… if it were my guess. Me?,… I would be tearing something apart,… if applicable,.. and have me a quick look/see.

      Chris


    • Mike,
      Sounds like a hand pump issue. The reason it is hard to pull up is a vacuum, the inlet check valve is not working. Here is a link to a YouTube video showing how to disassemble and repair a hand pump. I have not viewed it, but it’s like 50 minutes long so it should be pretty comprehensive. I have just a cheap ($85) Chinese hand pump and it’s worked flawlessly for almost two years. Secret is don’t let it get hot. Go slowly and let the pump rest if it starts getting hot, maybe 50 strokes. Open the pressure release to allow any collected moisture to expel. Good luck.
      Geo https://www.youtube.com/watch?v=_R2aiKOQDuo



      • Geo,

        I watched the video. He got it working. I hope he learned a lot in the process. Based on the symptoms, the problem was the check valve. This was the last thing he looked at and corrected. It was the first thing I looked at and I didn’t need to go further.

        ~ken




            • I would guess that the O-ring was never installed correctly from the factory. Interesting looking part. I’ve never had to disassemble my pump, but then I don’t use it a lot either. I did have some leaking issues when I first got my hand pump. It would pump up to pressure okay but when I stopped pumping I could see the pressure gauge slowly dropping back. I used Teflon tape on all of the fittings but was still seeing it creep back. I ended up sticking the bottom of the pump into a bucket of water to locate the leak. A bit more tightening on a fitting and no more leaks since.
              I have the Gamo Urban which has a proprietary fill probe. You may have seen how I used a pill bottle to protect the probe from contamination, but in case you didn’t, here is a picture of it.
              Geo


    • Ken,

      In a high pressure hand pump there are several chambers. It”s nothing like a bicycle pump that sucks air into a single chamber on the up stroke and blows that same quantity of air from that same chamber out the hose on the down stroke. It, instead, pumps air from one chamber to the next, where a mechanical advantage allows that same bit of air to be pressurized further and then transferred and pressurized some more, hence the name, “three stage pump”. This is why it’s also important to pause at the top and bottom of the pump stroke. Some think that it is simply to prevent overheating, and it does do that, but additionally it gives the air inside those chambers an opportunity to FULLY move to the next chamber through the tiny orifices that are provided and will save you many wasted strokes if you can get into the habit of pausing a second at each end of the stroke. BB has been preaching this technique for at least as long as I have been a reader.

      Having pointed all that out, I want to suggest that, perhaps, one chamber within the pump may be unwilling to accept air because the air that was in it previously was not expelled into the gun or into another chamber, on a subsequent pump, and what you sense as a vacuum PULLING your handle down could, in fact, be highly pressurized air in that middle chamber PUSHING your handle down. What happens if you pump the pump handle up and down with everything disconnected from the gun?

      I agree with the others that suspect the pump.

      Half


    • Ken
      Sounds like the pump is hydraulicing. In other words it has liquid it in it. Or grease.

      There is a check valve inside that can get clogged up in a sense.

      I rebuilt a couple different hand pumps I had before I went to a compressor.

      Also the fill hose where it screws into the pump could have some contaminants in it. Unscrew the hose and fitting from the pump and see if you can now pump. If not it’s probably that check valve I’m talking about.

      If it is the check valve the pump needs to come apart and cleaned. Probably doesn’t need new seals yet even. They are pretty easy to rebuild.

      Let us know what you find.


  11. Well, it was a pretty nice day today. Low 60s, sunny, no wind. Shot my Tomahawk some. Tried the Hades today. 10 shot groups at 25 yards that would hide under a quarter. 🙂

    Sat on the porch with Mrs RidgeRunner, sipping wine, watched the Sun set.

    Life is good.


  12. B.B.,

    I offer this simply as something I find very interesting. Not everyone will have the same amount of interest or time to bother with it. The author of these pages presents an interesting picture of tuning a Marauder. Warning: includes math I will have to study for a while to understand it well.

    Here is the home page, with links:
    https://sites.google.com/site/davemyownself/home

    I hope you are having good holidays with family and friends. I am definitely thinking about you at this time of year.

    Your friend,
    ~ken


  13. Translation problems.
    Too bad the Polish did not become big players in airgun manufacturing. I hardly had any problems understanding them in English. To this day I will always remember to close the basement light when I leave. My Grandmother was from Poland.

    I think some translators just get a kick out of using words with many meanings in an incorrect manor, sort of like an inside joke.
    Bob M


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