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Education / Training The Diana model 10/Beeman 900 target pistol: Part 3

The Diana model 10/Beeman 900 target pistol: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Beeman 900
The Beeman 900 pistol is another form of Diana’s model 10.

Part 1
Part 2

History of airguns

This report covers:

  • Godfather’s Gold Gun Giveaway
  • Shooting the Beeman 900/Diana model 10
  • The test
  • RWS R10 Match Pistol pellets
  • Qiang Yuan Training pellets
  • Gamo Match pellets
  • JSB Match Heavy Weight
  • H&N Match Green
  • Discussion
  • Summary

Godfather’s Gold Gun Giveaway

I am selecting the winner of the Godfather’s Gold Gun Giveaway this weekend. After my selection I will contact the winner to see if the airgun is legal in his locale. I hope to announce a winner on Monday.

Shooting the Beeman 900/Diana model 10

This is a day I have long awaited. I have shot these pistols in the past, but never under my strict test conditions, so today I hope to start the “book” on this one!

The test

I shot the pistol rested at 10 meters. The pistol was rested on the sandbag, touching the bag just ahead of the triggerguard. That is okay because the Beeman 900 is recoilless.

I shot 5-shot groups because target airguns often make groups so small that shooting more than 5 is just a waste of pellets. I wore my 1.25-diopter reading glasses that make the front sight sharp and clear, which I always do with an open-sighted pistol.

I had no idea where this pistol was sighted, but I shot for group size and wasn’t as concerned with where the pellets landed. I could always adjust the sights as I went.

RWS R10 Match Pistol pellets

First to be tested was the RWS R10 Match Pistol pellet. I suspected it might be the best pellet for this pistol, just because of how carefully they are made.

I checked the target after the first shot to make certain the pellet hit the paper. After that I never looked again. The first shot was low in the 8-ring. But when I saw the group I was disappointed. Five R10 pellets went into 0.92-inches at 10 meters. That’s what a sport pistol should do — not a target pistol!

Beeman 900 R10 group
The Beeman 900 put five R10 Match Pistol pellets into 0.92-inches at 10 meters. I expected to see all five in something like that three shot group in the center.

Since the R10s shot low but seemed well-centered, I adjusted the rear sight up 7 clicks.

Hunting Guide

Qiang Yuan Training pellets

The Chinese Qiang Yuan Training pellet that was next often surprises me with its accuracy. But not today. Five of them went into 0.865-inches at 10 meters. That’s not much better than the R10s.

Beeman 900 Qiang Yuan Training group
Five Qiang Yuan Training pellets went into 0.865-inches at 10 meters.

Obviously 7 clicks up was way too much adjustment, so after seeing this group I dialed the rear sight down three clicks.

Gamo Match pellets

Gamo Match pellets are certainly not world class, but I have seen them do some surprising things in the past. So I gave them a chance in this pistol. But they blew it!

I miscounted while shooting, so I shot 6 Gamo Match at this target and they went into a group measuring 1.253-inches between centers. Not much I can say about that.

Beeman 900 Gamo Match group
Six Gamo Match pellets went into a group measuring 1.253-inches between centers at 10 meters.

After seeing this group I dialed the rear sight another two clicks down.

JSB Match Heavy Weight

Next I fired 5 JSB Match Heavy Weight pellets. This time things were better, though not as good as I had hoped. Five pellets landed in a group measuring 0.789-inches between centers. This time the group is almost perfectly centered, so I planned to leave the sights alone from this point on.

Beeman 900 JSB Match Heavy group
Now we are getting somewhere! Five JSB Match Heavy Weight pellets grouped in 0.789-inches.

H&N Match Green

The last pellet I tested was the lead-free H&N Match Green. These did well in the velocity test and have been accurate before in other airguns. In the Beeman 900 five of them went into 0.888-inches at 10 meters. It’s too open to be exciting, though it’s not much larger than the JSB Match pellet group that is the best of the test.

Beeman 900 HN Match Green group
Five H&N Match Green pellets went into 0.888-inches at 10 meters.


Today’s test was disappointing. What you see here is not what I expected. I expected far better. The trigger is spot-on and we know the pistol has all the power it’s supposed to. But try as I might I just could not get this pistol to shoot. I expected a gold dollar group today (under 0.15-inches) but we didn’t even come close to a trime (under 0.20-inches).

I do note that the heaviest pellet was also the most accurate. And my first Diana model 10 did well with the 8.2-grain RWS Meisterkugeln. So a second test with heavier target pellets is in the works. I won’t do it right away, to allow us to see some other historical airguns in the interim, but I will return to this pistol.


That’s it for today. Sometimes things don’t turn out the way you expect them to, but you just keep on trying.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

204 thoughts on “The Diana model 10/Beeman 900 target pistol: Part 3”

  1. B.B.,

    Time to inspect the crown and bore with your endoscope, it might reveal something. Since the seal has been recently been changed it might need some breaking in.


    • I agree. Don’t they shoot test groups with their match pistols before they leave the factory? How did this one make it out of the factory? Something else has happened since then.


  2. Hello, I have seen a great disparity in accuracy with some of my Match pistols if the head size is
    smaller than 4.50 mm. Most of my Match pistols prefer 4.51-4.52 mm. Their groups really start
    to open up when the head size is 4.49 mm. Best of luck.

    • Paw080
      That’s the kind of information that makes this blog a real treasure.

      I was going to order the new SIG reflex sight the second I saw it in the pictures. I was hoping the be one of the first in case the word got out but then total and complete disappointment set in, and I may need to see a shrink to get over the devastation. I actually noticed the fine print in one of the pictures that said the real steel 9mm SIG M17 pistol in the picture DID NOT come with it! $49.99 would have been a great deal.

      I was so glad I read that fine print and saved the real disappointment of it not showing up in the mail box with the attached SIG 9mm pistol. Then I thought, heck I can use it on my SIG M17 airgun so I will probably order it anyway.
      Bob M

  3. BB,

    Paw080 could be on to something there. Whenever you find your round tuit for this air pistol again, try some of the larger head size stuff.

    Were any of the pellets fitting tight in the breech? Maybe a deep seat would help?

    Just maybe, the rest affects this sproinger more than you think it would.

  4. Bummer. Paw080 and RR are probably right. I know it’s recoilless, But, I seem to remember you having better luck shooting free hand one time or another. I too was expecting the trime being used in the worse case and the gold coin in the best. Bummer.

  5. Yesterday’s pistol with the AA Falcon domes- 13 fps spread (discarding the low speed first shot) gave you a .717” 5 shot group.
    Today’s gun with JSB Match Heavy Weight- 12 FPS spread gave you a .789” 5 shot group. I think you should try a different rest/hold as Rk suggests.

  6. Going to try reading glasses next time I can get some range time in, B.B. – that may help my shooting eyes, which seem off lately. Not that FM has ever been an outstanding shot; still, given the current ammo availability and price situation, no point in wasting ammunition either. Gotta get my Round Tuit and get that Crosman 38T fixed as well. It will enable more frequent and substantially cheaper target practice.

  7. The first and last two groups looked like there was a decent three or four shot subgroup formed, but the other groups didn’t seem to have subgroups. Well, only accurate airguns are interesting, especially if they are being inaccurate for some mysterious reason!

  8. BB

    Could it be someone has misused a cleaning rod from the muzzle end and damaged the crown? Inspection is needed as Siraniko suggested. Hope you don’t have a lemon. Is there any assurance this pistol ever met accuracy specs?


  9. I just went through one of these for a friend and it did not like being rested on a bag at all. I ended up resting my wrists on the bag and not the pistol. Kind of like going to an artillery hold it tightened the groups right up. Also I don’t disagree with checking the crown and breech for any burrs/wear.

  10. The P1 shoots better resting on the wrists. Chamber oil in the barrel opens groups up.
    How do you determine the piston timing accuracy? Seems like that could be an issue.
    The FWB 65 uses the sliding action design, I wonder which is better/ simpler. The FWB
    has a more elaborate casting for the pistol action, and gets away from the tubular steel design of the
    Diana. This pistol is a long way from the ‘New King’, even though the New King was state of the art commercial manufacturing for it’s day. 70 years of progress in this spring gun design, and it is obsolete now. Hope you show off the FWB!

    • Rob the piston timing on these is kind of either it works or you just made a pile of broken parts. I have been inside several of these and I personally feel there is more wives tales and folklore than anything else. Yes you have to be careful and measure, measure, measure but not particularly difficult. Given the chronograph numbers of this gun I think the pistons (and seals) are working well. The one I cleaned and lubed definitely didn’t like being rested on a bag at all and it definitely shot down in the “trime” zone.

  11. Incase anyone wants to know the 499 barrel adapted so it will fit some Crosman and Benjamin guns was a fail. For now anyway.

    I posted some comments on the Springfield Armory M1A report 2 of what happened using the barrel on the 1377 and 2260 I tried the 499 barrel on.

    • Very cool and interesting experiment, and kudos for taking it on. Too bad the results weren’t up to par, so far anyway. Do you think the original steel part of the bolt/probe is (or can be) magnitized enough to hold a BB without the need for the added magnet? And I’m sure you are aware, but the barrel has to be free of oil for any hope of accuracy.

      Good luck, and thanks.


      • Cobalt
        I tryed magnitizing the bolt at work on the surface grinder magnet. It’s a very strong magnet. We magnetize our Allen wrenches and screwdrivers and such on it all the time and works real well.

        The bolt I tried was from the 2260. Its plated chrome or something so I think that was a problem. I need to get a Maximus or Discovery bolt that is just metal. I think it will magnetize better.

        But Chris had a suggestion of dimpleing the barrel back at the breech end and load from the muzzle like the 499 does. I think I will try that next.

        I was also thinking about pressing a piece of plastic in from the breech end of the barrel with a hole in the center. Basically something to stop the bb when I load it from the muzzle. Still got to figure something out incase the bb trys to roll forward.

        Only if it wouldn’t get those 3 flyers in different directions it would be a success. It would group 3 or 4 bb’s in a row touching each other at 10 yards. So something is right about it all. Just got to figure out why the off shots keep happening.

        I’m going to keep trying. Was going to try to do some spaghetti shooting today but just feel like kicking back and relaxing with some other guns after the 499 barrel stuff. I will try more though.

          • Chris
            I’m going to try some more.

            Got to get a plan figured out for round two first though.

            Not today though.

            Enjoying the day and my other guns. Trying to have a no stress day. 🙂

              • Minute Of Something
                I’m going to try again.

                I think I’m going to try to find a plastic tube the right size for the barrel and press it in the breech end of the barrel a little past the transfer port hole in the barrel.

                Then I’m going to load the bb from the muzzle end. I just got to find a way to keep the bb from rolling out the barrel.

                Going to mess with it today in between shooting my other guns. And I am still going to try shooting the spaghetti out of one of my guns. Probably I will try the 2260 first and see how the rifled barrel does. Then try the spaghetti out of a smooth bore.

                Hopefully I will do that all today.

    • GF1,

      I was hoping for better accuracy. Maybe try one pump in the 1377. I wonder if you are having too much air following the bb at the muzzle. The intermediate ballistics may be causing problems with too much air following the bb as it leaves the short barrel. Have you inspected the crown carefully?

      You could try a lighter and shorter hammer spring. Does it have much of a pop ie pressure left as the bb leaves the barrel?

      Well that’s all I got.

      • Don
        Tried one pump and the bb didn’t make it out of the barrel hardly.

        And at 10 pumps it did make a pop when the bb left the barrel and also with the 2260.

        And the crown is perfect.

        The 1377 gave the best results at 2 to 3 pumps. I never chronyed but I’m guessing around 3 to 400 fps.

        I think its something to do with airflow at the breech. I need to see if I have any other transfer port orifices. Maybe that needs messed with. I used the factory 1377 transfer port orifice and the factory 2260 transfer port orifice. Maybe it needs to be reduced with the inside diameter.

        That’s why I’m not giving up yet. There was something causing those wild shots. Just got to find out why.

        • GF1,

          I think you are correct on the transfer port with a short smooth barrel.

          You need a magnetic steel probe like the copper one on my garden hose nozzle below. It goes past the transfer port and provides straight air flow down the barrel. The old Benjamin pumpers transferred the air thought the bolt/probe into the barrel. It still needed to make a 90 degree bend though but did give it more time to smooth out. maybe.


          • Don
            That’s what I did for the probe magnet with the 499 barrel. I thought that getting the bb past the transfer port hole would work. Guess you missed where I said I super glued a magnet on the end of the 2260 probe.

            And yep I remember the hollow probes the Benjamins used.

            I think a small inside diameter transfer port hole is needed like the one of two transfer port orifices that come with the 1720T. And no the transfer port orafice is different for the1720T so that is a no go.

            I’m sure the 499 gun works on very low flow of air. Even when upping the spring pressure like Chris and others have done.

            There is probably just to much excess airflow left over with what I’m doing with the 499/1377 and 2260 combination I’m using. Its probably blowing the bb around after it leaves the barrel.

            But then again.why do I get 4 bb’s stacking in a row when I’m shooting groups. I’m still bummed about the flyers. I thought it was working till the flyers started happening randomly.

  12. Woohoo! They have done it!

    TCFKAC has finally brought out a multi- shot sproinger! Hip, hip, hooray!


      • Fish,

        LOL! I was being sarcastic. Quite frankly, I would take the Gamo over this. This action requires an extra step in the firing cycle compared to the Gamo and Hatsan.

        I myself am more likely to purchase the Umarex Synergis over any of the above. Just my druthers.


        • RR,
          I was serious, because the magazine is not high as hell with Crosman – so I really liked it better. Synergis is the best as the magazine is on the side – not all over the front of the scope.

          • Fish
            Leave out the cuss word hell.

            I keep getting in trouble when I do that on the blog.

            But it seems others do it randomly and BB doesn’t say anything.

            So what the heck. I guess go ahead until BB says something.

              • Fish
                I don’t care what anybody says.

                But if BB gives me crap about it and not somebody else then I got a problem with it.

                That’s what I’m talking about.

                BB says it’s a family blog. Which is cool but no double standards. I told BB I would point it out when it happens.

                Next time I’ll just say to BB is, cussword and and shake my finger.

                That’s what happens when you don’t have any blog police. 🙂 Or double standards.

        • RR
          I think your including the wrong person in your comment.

          I said BB has said something about comments I have made but not about what others have said.

          I say if you can’t cuss I can’t either. Is that a little more clear.

      • Chris,

        Not you also?! I am going to have to watch the sarcasm. I am most definitely needing to make it more obvious.

        Years ago, I can recall TCFKAC was on the cutting edge of airgunning. Then they let go those who took them there and hired a bunch of business flunkies who had no idea what they were doing, airgunning or otherwise. Since then they have been playing catch up.

        Some are oohing and aahing about their SAM. As for myself, they should have brought out the side lever Marauder a long time ago. Will the SAM be a success? We shall see. I am certain the Mattelomatic crowd will whine that it does not look more like one and the aftermarket crowd will do everything they can to make it so.

        Me? Give me a Maximus. I will refine it myself.

        • RR,

          I have been out most of the day and gave it a (quick) look over from your post. Trust me,.. I am on to gimmicks,…. but also too,… like I have said many times,…. I do like to see innovation. Nothing more.


          • Fish,

            Hey, I am an old salt. It is a habit I am still fighting and will likely fight until my dying day. When I communicate this way, I have more time to think of what I am trying to say. I also have the luxury of proof reading.

            Quite often when speaking, I most often say something without much, if any thought. Sadly, I cannot erase or change the words either.

            Somehow, even here I still manage to offend some people on occasion.

            • RR,
              You’re good. No worries. I was actually agreeing with you on the matter…
              I sometimes tend to preach at people on certain things and turn into someone I actually hate. I’ve lost so many good friends. I’m still teaching myself to accept people the way they’re and find things to love about them instead of judging them. Everybody has an amazing story in this world. When one decides to judge all the time, then he has no time left to love. The sad thing is I judge myself in the most brutal way. I don’t know if I will ever make peace with the silly man I see in the mirror every day and night.
              If you knew how much of a fool I am, you wouldn’t worry about half the stuff I say. Life is a long, long journey, and every lesson I learn throws me back to the start; the more I learn, the more I realize how ignorant I am.

        • RidgeRunner,

          “Since then they have been playing catch up.” Is that what they call it!

          And here I thought they were just trying to regain Market Share…
          that had been “stolen” from them…


  13. B.B.

    I see it is not just multi shot PCP’s that need a shot counter. I usually place the # of pellets that I want for a group outside of the tin and sanding upright.

    From what I gather, this is the third Diana 10M that you have owned. You said that you loved the first 2, yet you got ride of them. The airguns that I love-much fewer than your horde I’m sure-I would never part with.


    PS just shoot the darn pistol free hand!

    • Yogi,

      Yeah, I do that too, with pellets. But this time I didn’t.

      I do plan to try a different hold next time.

      As for getting rid of guns, it comes down to not having the monery or the room for all of them. I have a core that I hold onto.


      • BB
        I like that. A core to hold on to.

        I found that I have a core lately too.

        My problem is that my core are accurate guns and I want to keep shooting them all.

        You know what I have been doing? Shooting them all. 🙂

        • GF1,

          There is nothing like a nice, sunny day on the back porch with all the old gals here at RidgeRunner’s Home For Wayward Airguns. We all enjoy sitting here and plinking at the various spinners and empty CO2 cartridges or hunting the occasional feral soda can.

          By the way, one of the “core” can be pried out of BB’s hand, but you had better bring it. 😉

          • RR
            Yep and has been really nice the last several days and is suppose to continue into the middle of next week. I’m trying to take in as much as I can while I can.

            There is a 2 mph wind coming from behind me which a tree line and the house blocks that. So I have like zero wind right now. You know what I’m doing. 🙂

  14. B.B.,

    You are getting some good advice from some of your readers! I kept wondering about your choice of hold/rest: “…touching the bag just ahead of the triggerguard. sandbag contact point!” Normally NOTHING would be touching the pistol in that area and, if i understand the actual contact point with the bag, it looks like it touches point(s) involved with cocking action. Although you didn’t specifically say one way or the other my assumption, given the target grip, was that your weak hand was completely out of the hold picture? I’ll add that i also question the optical accuracy of (drugstore?) readers; if they are angled to the sight/target the potential distortion differences shot-to-shot might be enough to cause almost all of the vertical dispersion and some of the horizontal component too!
    Now that you have your eyesight stabilized you might want new targetshooter frames and/or Rx quality optical lense(s) if you already have some shooter frames you like.

    Must be frustrating to have this level of performance from this particular old girl! Hope you get it sorted.


    • Shootski,

      I too questioned the resting of the pistol. It IS a sproinger. Even with the counter piston, there is some movement and vibration. You can probably get away with it with the Whiscolme (sp?) because you just about have to rest it, but this is so much lighter than even the 72 and 75. It would not take much to open those groups like that.

  15. Ok everybody.

    I’m in trouble now. I was going to get some spaghetti and mini marshmallows to try the spaghetti shooting in my 1377 with the 2250 barrel.

    My wife and daughter said nope.

    I said well looks like you got to go back to the store and get some for me then.

    I guess you already know where this is all going. Looks like I’m going to have to sneak me some out to try. 🙂

  16. Folks,

    Here is a detail of my design of a low pressure airgun valve. I sized the reservoir to have 10 times the barrel volume as a starting point. I wanted a valve that would have very little pressure loss from the reservoir to the barrel. I also wanted a valve to automatically close after the shot. Not sure if I will take this on as I do not have more than a drill press to machine the parts. I may try a version using PVC pipe fittings.

    So far I have tried three different off the shelf valves and a 22 caliber Maximus barrel:

    1. an air compresser blowgun valve, it was very inconsistent in velocity.

    2. A natural gas petcock valve, also very inconsistent in velocity.

    3. A garden hose spray nozzel, good consistentsy velocity and 400 fps with .22 caliber AA Falcon pellets.
    Here is a 5 shot string: I checked the pressure after the test and saw it was 135 psi.

    Shot fps
    1 400
    2 401
    3 398
    4 400
    5 401

    I think the garden hose spray nozzel gives a good proof of concept. I thought a 22 caliber barrel would be a little better than a 177 caliber barrel due to less losses in the larger diameter air pathway. Not tested though.


        • The garden hose to air fittings are for RV’s to blow out the water lines for cold weather winterizing.

          The probe is a flare fitting to pipe thread adapter fitting threaded into a brass garden hose end cap. The probe is a flared copper tube.

          • Don
            Thank you.

            You know one thing I have always said is possible is low air pressure airguns. As in shop compressor airgun pressure.

            We made some pretty accurate hard hitting airguns at work. Really no joke.

            Liking what I’m seeing.

            • GF1,

              There have been many advocates of LPA over the years. The powerful airguns of the 1700’s operated on 600-800 PSI. A high powered sproinger only develops around 1000 PSI. As you well know, the Disco/Maximus operates at 2000 PSI max. The Marauder can be tuned way down.

              As you well know, the secret is the volume of air used per shot, not the pressure of the air. The high pressure only means more volume of air is being stored in the available space. The secret is the dwell time of the valve and how much air is it letting out behind the projectile to push it down the barrel.

              Yes, the pressure of the air allowed to escape does have an affect. The higher the pressure, the less dwell time of the valve. Also, the higher air pressure will have an increased affect on the velocity of the projectile. However, once the projectile exits the muzzle, any further expansion of the air is wasted. Most modern PCP’s are very inefficient, hence the shrouds and silencers.

              But you know all this. Just preaching to the choir.

              • RidgeRunner,

                Visualization drill!

                Initial gas flow from the valve/TP at highest possible pressure allows the gas to expand “away” from the base of the projectile and not flow down the barrel behind it any more than is absolutely necessary. As soon as the gas flow is moving down the barrel the Mass of the gas behind the base is actually added to the Mass of the projectile.
                Drawing even a weak vacuum in front of the projectile reduces the total Mass and Acceleration of the shot in much the same way.

                Does that sound right to you?


                • Shootski,

                  No, it does not. It seems to be almost completely backwards.

                  As the projectile begins to move from the applied force of the expanding HPA, the gas will indeed further expand to fill the volume. If, the barrel is long enough, the pressure will decrease to the surrounding atmosphere or if the barrel is even longer, the projectile moving down the barrel can actually create a vacuum behind it, slowing it down. That would be a pretty long barrel.

                  If, you create a vacuum in front of the projectile, it will be “drawn” down the barrel, assuming it overcomes the “coefficient of friction” until a state of equilibrium of pressure in front and behind occurs. By creating a vacuum, you are also reducing the mass that the HPA must overcome, accelerating the projectile further.

                  Once upon a time I had the formulas for calculating all of that stuff. I do know where to get them.

                  My question is, were you being sarcastic?

                  • RidgeRunner,

                    Not completely, certainly not like down below about Market Share!

                    Internal Balistics are not as well understood as many believe. The formulas you have i suspect are in my files as well. Unfortunately they are how we have always thought about them is what some recent modeling seems to be showing.

                    “As the projectile begins to move from the applied force of the expanding HPA, the gas will indeed further expand to fill the volume.”

                    Im at the split second prior to the projectiles inertia being overcome by the pressure. At that point we need to get maximal pressure in a PCP. Once the projectile starts moving down the barrel the key seems to be to hold that pressure steady with continued flow (but only enough to makeup the presure head) through the TP. That is the point that we need a breakthrough. The Gas Laws seem to breakdown when we get to view them with modern Timing’s ability to provide stable time division units of ever smaller size. There are waves of pressure within spaces that we were taught in high school Science/Physics class were to be considered uniform on all surfaces of the pressure containment vessel. I think the Spring Piston and PCP powerplanr advantages need to be some how combined to get maximum performance.

                    Imagine Hybrid with a plenum at hpa pressure with one end being a spring piston being compressed through some check valve on into the barrel providing pressure rise RATES either powerplant alone can only dream of creating. Can it be made to work without too much weight or complexity? I’m not certain, but it seems to ONLY require a synchronized triggering/sear system.


                    Does that make more sense than my first try did?


        • GF1,

          I just remembered I have two Apache Fireball 177 barrels that are smooth bore. I may give them a shot with low pressure and bbs and pellets. I will have to make a smaller probe though.


      • Benji-Don,

        You need to get some BALISTOL on the upper trigger by the hinge point… can’t see letting corrosion start during R&D. Lol! No SAFETY! Thank the gods!

        What a great project!


        • Shootski,

          As you can see it was pretty bad when I first tried it. I lubed it good with synthetic 5-30. Won’t waste Balistol on that, I need to pick some more up.

          I expected some comments on my valve drawing? I can almost visualize making it out of 1 1/2 inch PVC pipe and fittings. A beveled faucet gasket should work as the valve seal. Even with a simple chamfer instead of the ellipse curve in the drawing should allow good flow.


          • Benji-Don,

            “I expected some comments on my valve drawing?”. You did?

            Looks like a concept that has worked before! The devil is in the detail of construction and sealing all the possible points of air leakage. I think you will need a (hard viton or nylon?) gland washer on the valve stem (rod) on the inside of the air reservoir at the nock open end. I also think you need to rethink your valve head. On a internal combustion engine that would be perfect to cause the turbulence you want in the combustion chamber but this is an exhaust valve and turbulence will cause back pressure and you don’t want that. I would go with a flat pointed cone or a convex cone the longer the better; if you can find one to minimize turbulent flow into the barrel.

            Is that enough comment? Lol!
            Remember you asked for it and it was FREE of cost!


    • Benji-Don,

      You need to rethink the valve seat and the spring direction of action and seating! Right now it looks like a Knock Closed Valve to me. Maybe I need more/stronger coffee?
      It seems to show: It knocks open to the left and the valve head has no place to go on the left? Also the weak spring is used to return the valve to the closed position….


      • Benji-Don,

        Belay most of the stuff i wrote! I had a cup of Expresso and now it all makes sense. I got turne around until i started with the Striker Spring, Sear, and Hammer (Striker) my bad!

        I still think a cone to smooth the flow on your valve into the TP is needed.

        Not going to shoot targets after that Expresso shot!


        • Shootski,

          Thanks for the comments, I spent 30 years answering and making comments LOL I am not thin skinned. I’m not an expert on air flow. My valve design is backwards from most airgun valves. The springs, location of the sear etc. Could all be used to tune the valve. There would be a triad off between air Los where the rod exits the reservoir wall and ease of movement. With a shop compressor a little air loss is not a big deal. Maybe a bonnet with a compressible seal would allow adjustment between air tight and ease of movement.

          I wanted the area in front of the seal to be so large the air velocity would be low to thus reducing turbulence losses. That is kind of what is happening with the hose nozzle.

          You may be correct that the seal shape could greatly reduce the turbulence losses. I could also reverse the curve at the outside boundary to the reservoir wall. I did get 400 fps with 135 psi. With an optimum design what is the max fps?. Larger reservoir more streamlined air flow maybe 600 fps with the same pellets. I was thinking of a jet engine nozzle for the shape. I have used parabolic and hyperbolic curves for water flow designs but went with an ellipse for this curve.

          The more comments the better. I am trying for function and maybe form latter. I have never been an artist. Wish I had a machine shop at my disposal.


          • Benji-Don,

            I wonder what Girardoni’s shop would have been like. He probably had a human powered drill press, lathe/boring machine and maybe a grinding wheel; the rest would likely have been hand tools. It would be extremely interesting to be able to time travel to various shops of the Craftsmen and Gunsmiths who created the early airguns.

            If you go the PVC route think of 3D printing.


            • I would be ecstatic to be in Girardoni’s shop. When I built a steam engine from scrap from out back in high school for my physics class and the teacher hid under the desk and others called the cops because they thought it was a bomb I knew it was uphill from there on. I don’t know if I want to go with 3d printing, but that may be a way to go. Especially at 100 +- psi.


  17. BB,
    Sorry for the late comment on the Diana 10, but in my experience the hold could be the problem. My Diana 6G does not like to be directly supported on the sandbags and I got my best groups with the wrists supported by the bag and using heavy MK pellets.

    In my limited experience the Giss system works but it is not as consistent as I hoped it would be. Just my $0.02.


  18. Update on the 499 barrel adapted to work on my 1377 with the steel breech.

    I figured out how I’m going to muzzle load the bb and keep it away from the bolt probe and away from the transfer port hole.

    I took a Daisy wadcutter pellet and drilled a .062″ (a 1/16″ drill bit) hole in the pellet. Then put some super glue around the head and waist ofthe pellet. Then I pushed it in from the breech end of the barrel past the transfer port hole in the barrel.

    I waited for the glue to dry and ran the drill back through the hole in the pellet by hand just to make sure the hole was still clear. I put a bb down the barrel from the muzzle end and seated it a little with my wooden dowel rod. The bb stayed in place when I pointed the barrel down. I made sure the bb was still against the pellet with the hole in it and it was. I blew through the breech end of the barrel like a blow gun and the bb shot right out.

    So I’m putting the 499 barrel on my 1377 right now to give it a try again. I hope the pellet stays seated. If not I’ll probably try one of those refrigerator magnets wrapped around the barrel at the breech end of the barrel like Shootski mentioned.

    Fingers crossed.

    • GF1,

      The magnets on the barrel did not hurt anything. I can’t say it made anything better, but not worse either. At the point you use them, a Ram rod is a must because the bb will stop at each magnet.

      How about putting the coupler nut and funnel back on?

      On mine, I took a piece of clear PVC tubing, split it, put it on the barrel and electrical taped wrapped it. The idea was to reduce vibration. That is how it is now. Did it help? It did not hurt.

      The magnets I got at Walmart in the craft section. The smallest I have are coin shaped and .315″ diameter and .117″ thick.


      • Chris
        Want to say this first.

        I wanted to try the spaghetti in the 1377 with the 2250 barrel before I put the 499 barrel back on it. Problem is I don’t have anything to put on the spaghetti to get it seal to the barrel. And if I try cutting a piece off the marshmallow it gets sticky. So I don’t want to put that in my 2250 barrel.

        But I tried this. I took a couple Q tips and cut them in half. I loaded one with the cotton end first from the muzzle and pushed it down to the probe with my wood rod. I hit a aluminum can at 10 yards 2 out of 4 shots. That was 10 pumps. And one of them penetrated the can with the stick part and stopped at the cotton. The other one I hit with dented the can real good.

        Anyway wanted to say that first. But check this out. I put the 499 barrel on the 1377 and I loaded from the muzzle. Here is the good thing if I give the bb a little tap, tap with the wood rod the bb stays in place up against that pellet with the hole in it I super glued in the barrel. So that’s good news and no magnets needed. And if I don’t do the little tap, tap the bb will roll out.

        But I tried 3 pumps then 2 pumps and so far I have not got any fliers and 5 shots hit with about a 1 inch group at 10 yards. So again more good news. Now I’m going to increase the amount of pumps and see what happens. Hopefully more good news. Getting ready to do some more testing now.

        Oh and forgot. No room to but the Daisy muzzle piece on the barrel. It would hit the air tube and also the front sight on the 1377. The 499 barrel is too short.

        • GF1,

          Sounds good. I think you could use a cotton ball and tear off a small bit and super glue that to the spaghetti. A piece of plain string can work too. Some cotton swabs have plastic shafts that are hollow, so that might a solution for the spaghetti.

          A simple tape wrap built up to the barrel ID would work too.


    • Didn’t get to post last night. My daughter and her husband and the grandson came over unexpectedly. That was a nice surprise.

      But about the 1377 and 499 barrel.

      Groups did get better with that last mod to the 499 barrel and loading from the muzzle.

      But… still not what I was hoping for. Not going to post the pictures I’ll just tell what happend.

      I was getting 10 shot groups at 10 yards around 1.250″ to 1.500″ and still getting a random flyer out of every 10 shot group that was at 3 inches. I did try a few drops of oil and still exactly the same groups. So that didn’t help or make it worse.

      So next I tryed 15 yards and it was terrible. The groups were 3 inches and bigger.

      Next I came back to 5 yards to see if I would get a group like Daisy sent me with the barrel. The target I got from them looked like a ragged 5 shot group with all bb’s touching. Was around a .300″ group. The best I got was just under a inch like .950″ and out of 3 ten shot groups i got only one flyer. That made the group 1.500″.

      What I think is the 499 barrel could be longer. Either way the farther the distance the more it opened up the groups. And not a little but alot.

      And I have to say that I have shot bb’s out of a QB 78 I believe it was with a 13 cubic inch regulated HPA bottle. It even has a rifled barrel. It got groups out at 25 yards like what I was getting at 10 yards with the 499 barrel. And I have shot my smooth bore 760 with bb’s and got about the same results as the QB 78.

      So I still think that if the 499 barrel was longer there might be better results. But I believe I’m done with the 499 barrel experiment.

  19. RidgeRunner
    With you on the sarcasm thing. I send it flying over peoples heads all the time. Hope that entry above on the new SIG dot sight did not make me look too stupid.
    My long way of saying … Do they really think people are stupid enough to think they would be receiving a real SIG M17 pistol with the new sight, and believe they had to make the point they would not perfectly clear with a statement below the picture?
    And after being raised in Brooklyn followed by a career in the Navy, aviation maintenance and riding a Harley for years, foul language has worked its way into every sentence unless I consciously check it.

    • And for all those non mechanically inclined people out there, there are times when doing your job can be ‘extremely frustrating’. Like when you sacrifice your flesh or blood or you drop a small part from a car that ALWAYS finds it’s way to the dead center of the car, underneath it, or drop a small screw … when you are 40′ above the ground on a man lift.
      And you can ask just about any mechanic. A lot of times you just have to find the right cuss word to make a part fit right. They often leave it out of the maintenance manual so you need to try a lot of them. 😉
      Bob M

          • And Fish
            If the words do not come naturally just try sticking your fingers into a Navy A7’s belly air speed brake as it closes under 3,000 pounds of pressure. At first you may wonder if they are still attached on the other side but I’m sure the words will find their way out.
            But don’t be surprised if you say a little prayer afterward. It’s not compensation for the cuss words but for an entirely different reason. Like perhaps someone sees you and the jet does not start to take off with you attached.

            No A7 around? Just try slamming your fingers in a car door, really hard! Almost the same.
            Bob M

              • Fish
                Don’t really want to get too deep into it here. Best to google it. LTV A7 Corsair. Late 60’s carrier based single engine light attack jet. Between the nose and main landing gear there is a big hydraulically operated panel called an air brake that swings down into the airstream to slow down the airspeed. Basically the entire belly section. It has two side panels incorporated that fold out so it looks like a big shovel. Well it droops down when on the ground and not under pressure and makes a perfect hand hold when you are kneeling down to check gages in the wheel well. But, it slams shut when the engine is started up.

                May be able to see it in the pic. A big crack opening forward of the main landing gear door.
                BB, feel free to dump the pic if you want. I understand, not too appropriate here.

    • Bob
      I worked on cars for alot of years and worked in the machine shop business for many years. And of course how it was on the street. It’s very hard to not let a cuss word come out on every sentence. I have to catch myself all the time when management comes around at work. Heck everybody is like that at the shop. Even the girls. Heck they get going worse than the guy’s.

      At least here on the blog I can think before I write. But I can say that I try to watch what I say around the kids at home.

      Anyway that’s why I was saying something to Fish. If somebody else on the blog can get away with cussing then I better not hear anything if I cuss. That’s what gets me all the time. Double standards.

  20. GF1,

    I hooked up the 177 barrel from my Apache Fireball rifle to my hose nozzel. The barrel is about 20 inches long. When I finished the air pressure was 130 psi so it started at about 135 psi.

    I used some small rubber tubing to connect the barrel to the hose nozzle because the barrel has a double slit for about an inch on each side of the barrel at the breech. The barrel is crimped in at the slits to hold the bbs from falling out. I already know these barrels are not accurate so no expectations in that respect. I muzzle loaded the bbs with a wood dowel.

    I shot a 10 shot string and recorded the velocities:

    425, 347, 429, 423, 422, 415, 421, 420, 429, 426

    I think the 347 fps was me trying not to destroy my chrony and opening the valve slowly.

    When I was finished I probably shot about 20 shots maybe 15 into a new sheet of paper on my trap. The group was vertical about 0.8 inches high by 0.3 inches wide at 3 yards inside my shop. One shot was a little lower tha the rest, without it the vertical measurement was 0.6 inches.

    I don’t remember trying larger bbs in this barrel that may improve the accuracy. Not sure this helps with your 499 barrel project but does show adequate velocity for a bb gun on low pressure air.


  21. Chris
    I found one a long time ago on u tube. The guy used an air compressor hook up with PVC and had something like a rotating sprocket to feed the bb’s. Demolished his target. Another had 5,000 rounds per min.

    Just search ” Homemade full auto bb gun” or something close to those words.

    Way too much stuff out there now on the subject. May be hard to find but there is a lot of selection now.

    • Bob,

      I may do that. The smooth feed of bb’s I see as being an issue. I think that paint ball has the same issues? They could also be pushed by air,… but they would have to be pushed at a (higher) pressure than what is driving the bb’s down the barrel (otherwise,.. the bb’s to be fed would just be blown back/held back, out of the way.)

      I am thinking along the lines of,…………. as soon as the bb drops into the air stream,.. it is sent down the barrel. No “valve”,… per say. The bb feed/push would be at 125 psi (for example) and the propulsion pressure would be at 115 psi (for example).


      • Chris
        I see your point. From what I remember the rotating drum / sprocket prevented pressure from entering the feed port and then I remember something that used the air to syphon out the bb’s or they worked in conjunction with one another. Been a long time but yes it was a steady stream. If I ever find it again I’ll let you know.

    • Bob,

      I could not find the full auto bb gun I remembered. Wow there is so much out there I can not find it. The one I remember loaded one bb at a time in a semi controlled manner. It was simple but worked.


  22. Fish
    I was just engaging in some anecdotal conversation with all that stuff with the A7 and such. Hope you don’t think I was being facetious. Your reply went right over my head, sharp, but it may have ricocheted and hit me in the back of my head instead. Good blog today.
    Bob M

  23. “Daisy 880…my new plastic rifle”
    Hey all,
    While we have a few hours to kill till B.B. posts his latest report, I thought I would throw in a pic of my new plastic rifle, a Daisy 880 a gun on which B.B. did an extensive set of reports…
    (that are here: /blog/2014/05/daisy-880-part-6/ )
    Anyway, I got a $100 gift card on my Amazon Prime account and used it to buy vitamins…and there was enough left over to get a factory-refurbished Daisy 880…just to see what it was like, as I had never owned one.
    I knew it would be mostly plastic, and I was prepared to not like it.
    As B.B. noted, the pellets could be tricky to load, although I found a couple that were long enough to load without falling in to the BB loading port, Beeman Silver Ace and Beeman Ram Jet; both made a single hole on the 5-meter range, but at 15 yards, the Beeman Silver Ace pellets proved superior; I’ll use those till I find something currently made that shoots as well. This rifle is a nice little plinker that I am liking much more than I expected.
    Take care all,

    • Dave
      That white diamond just reminded me, I have one of those someplace. Came with a 4×15 scope, 800 fps with bb’s.
      Must be stored with that new, in box, car cassette player I know I have someplace too.

      A Crosman Legacy, another pumper, claims to be able to shoot alloy pellets at 1,000 fps and lead at 750 fps. May perform as well?
      Something satisfying about those pumpers. Light weight, low purchasing / operating cost, shooting anything you want with halfway descent accuracy. The kind of airgun you don’t mind sharing with a newbie. Not at all intimidating to kids as well.

        • Dave, there you go !
          Just noticed something with your pictures. You may need to shave down the seem area of the dovetail rail if you want good scope ring seating. If you desire to use one.
          Some dovetail scope mounts have no clearance for that slight hump. Did it to some of mine already, it really helps.

            • Dave,

              The last one I had was the scoped model. I had to move the front lens out to get it to focus down to a usable airgun distance. Not ideal, but it worked. Which is to say that it worked well enough for the accuracy of an 880. I do better with scopes and if I was to get another,.. I would scope it with something.


                • Dave,

                  Well,… I see that you are following that old gunner rule of spending at least as much on the glass,.. as what you spent on the gun! 😉 Or,… is it that you have to spend 2x? Or 3x?

                  Either way,… you will be all set.

                  The downside?,… you will have just eliminated all excuse for poor groups due to open sights or poor glass. 😉 Then again,… it is an 880,.. so you still have a little wiggle room.


                    • Dave,

                      🙂 Very good. Now you will truly know what it is capable of. I would like to mod. one and have tossed it out a few times, but not much ever really comes back. I am sure something can be done, but maybe not really worth it. On my Maximus, the trigger mods were so simple and made a huge difference,… so maybe something like that at least.

                      It has a hammer spring I assume,.. so maybe something there. I seem to recall something about one of the pump parts being discontinued, but maybe that only applies to old models.

                      At any rate, well done. Enjoy!


    • Dave,

      Nice. I have always had one, but not currently. I am sure I will be getting another one. I am not sure what year it might in the future,.. but maybe they will do a “special edition” and/or “anniversary” edition. A redo of the metal version would be nice.

      I did pick up an Barra 1866 awhile back, but have not played with much. Pretty much the same thing but styled different. No scope ability though. A guy on GTA make replacement muzzle ends that employ a peep sight circle to replace the front blade. Another guy adapted a peep to the rear. I mainly just got it to display. Some reviews on YT were pretty impressive.

      Enjoy,… Chris

      • “A redo of the metal version would be nice.”
        Chris, I agree; I was looking to get an old metal receiver one till I saw this one on Amazon.
        I got wifely approval (always important) because it was a “no cost item.” =>

  24. Just searched ‘Home made PVC bb guns’ and boy there is a lot of talent out there.
    Of course the search picks out key words and expands from there. It looks like most of the fastest ones simply pressurize the reservoir ( As previously stated ) and blow them all out in seconds.. A hand held button controlled air spray nozzle seems to be popular in the construction of a lot. Newer ones have a ‘Muzzle Brake’ tip mandated by OSHA to prevent injecting HPA into your skin. It gets diverted out the sides.
    Home made was popular back then because there were no full auto bb guns available. Except perhaps for that one that used a can of Freon? Kind of awkward.

  25. Chris USA
    Now this would knock your socks off. A home made, full auto, Ma Duce bb gun. Noticed the QD air fitting above the ammo can. And look at the size of the pressurized reservoir / receiver.

    • Bob,

      Very nice. I do not have the tools to machine or fabricate other than hand power tools. Any build would have to be simple in design.

      Like you suggested,.. a hard search would be prudent just to be sure that I was not just reinventing the wheel.


        • Bob,

          That sounds more like my level. I have done a lot over the years with only a little to work with. I am good at being innovative and re-purposing.

          Some of that air control tubing that is hard walled but flexible would make a nice magazine. Put a follower behind the bb’s and air pressure behind that. It would be a pain to load though. Still not as good as just dumping a bunch of bb’s into a well and having them feed out.


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