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Education / Training Taiyo Juki

Taiyo Juki

by B.B. Pelletier

Before we start, I’ve got a new video article posted on Pyramyd Air’s site:
How to hold an air pistol for greatest accuracy.

While I’m in NY filming the TV show, I’m drawing on some articles I wrote a few years ago. This blog about the Taiyo Juki air rifle originally appeared in Airgun Revue #2, which was published in 1998 and is now out of print.


Even if you’re not new to adult airgunning, the name Taiyo Juki may be one you haven’t heard before. I heard about the company only recently, which is no doubt due to the fact that their airguns have never been even remotely mainstream in the US. But some collectors seek them eagerly, which is how our subject rifle came to us for review.

Alan Becker, the “Schimel man,” called me with an offer I could not refuse. He had recently acquired a Taiyo Juki repeater that was quite unusual and interesting to him, and he wondered if I would like to give it a test drive. He told me that a certain collector had already spoken for it, but he sold it with the stipulation that I’d be given a chance to evaluate the piece before it went to its final home. Alan figured something as strange as this only comes along rarely, and he wanted as many airgunners as possible to benefit from the experience.

I won’t attempt to go into the history of the company or to describe the other models in their line. I’ve learned what little I do know from discussions with Greg Fuller, Steve Gibbons, Davis Schwesinger and Don Gunder, to name a few. Certainly, there are several other models of rifles in the Taiyo line, and collectors of Pacific Rim airguns scramble over each other whenever one becomes available.

Our subject rifle is called the Taiyo Deluxe and is a five-shot, bolt-action repeater in .177 caliber. It’s powered by bulk-filling with CO2 from a convenient fill tank, just like the Crosman bulk-fill guns. In fact, the Crosman tank works fine with this gun. Other than those simple specifications, though, this is a most unusual air rifle, as I’m sure you’ll agree after examining it.

The gun is short, but not necessarily lightweight, giving a feel of substance when held in both hands. The receiver is very wide, which translates to some added thickness in the stock at that point. Note the unusual cover over the action. It’s stamped metal on this example, but Steve Gibbons has seen one with a solid cover machined from a block of metal. What a feel that gun must have! The markings that look like engraving on top of the receiver cover are either painted or a decal. I was never able to determine which.

Above the receiver cover, two aluminum scope blocks extend upward like the mounts on expensive target rifles from decades ago. This is a strange look in an air rifle, but it seems to fit the Taiyo Juki ambiance quite nicely. The blocks are small, in comparison to what we see on modern air rifles; and, being made from aluminum, they are very fragile, too. Since this was a borrowed gun, I was very careful not to gouge them when tightening the ring base clamps, which would have been an easy thing to do with modern mounts. Of course, this is a CO2 gun, so there’s no need to over-torque the mounts because recoil is virtually non-existent.


The power adjustment wheel moves forward for power, to the rear to back off. Note the two tiny aluminum scope blocks.

No doubt your keen eye has already come to rest on the vertical wheel that protrudes from the right side of the receiver cover. Although the characters both fore and aft of this wheel are Chinese, any airgunner worth the title knows instinctively that this arrangement is a power adjustment feature. And you don’t have to read Chinese to know which way to go, either. Just figure out whether tension is being increased or decreased on the hammer spring, and you’ll know which way the power is going. There are also detent stops every quarter turn of the wheel to help with final adjustments.

[NOTE: We did say the characters on the gun are Chinese. One of our faithful readers, George Chiu, gave us the translation for them. They read “strong” and “weak,” appropriately enough. He tells us that the Japanese didn’t have a written language until the 10th century, when they went to China and brought back theirs. Many of the characters have been preserved down through the centuries, including these two. The character for “weak” is represented by two feathers. “Strong” is characterized by a person drawing a bow. Our thanks to George for providing this information.]

I tested the rifle on high power over an Oehler 35P chronograph at 74 deg. F and found that RWS R10 pellets move out the bore at 680 f.p.s. average velocity with–get this–only a 3 f.p.s. variation in a 10-shot string! That’s extremely close for any gun, not to mention one that runs on bulk CO2.

When I dialed the power wheel back to the lowest point, velocity dropped to 283 f.p.s., but the spread was a staggering 72 f.p.s. In all fairness, though, it was only the first two shots that caused such a large spread. Throw them out and the spread was a respectable 5 f.p.s. Crosman Copperhead wadcutters averaged 686 f.p.s. on high power, and Alan sent along his results with 7.9-grain Premiers–701 f.p.s. at 80 deg. F. So, the rifle falls well into line with other .177 CO2 guns having short barrels, like the Crosman 187.

The bolt must be cocked to fill the reservoir, which is common in a bulk-fill gun. What is not common is a secondary “hold back” notch to secure the hammer from firing accidentally. Just twist the bolt handle down to the right when it’s pulled all the way back to cock and it engages a safety notch. What a bright idea! Now there’s even less of an excuse for any unfortunate incidents while the shooter is working around the business end of the gun.

Another feature I find fascinating is the safety. It allows the shooter to select automatic or manual safety operations! You can set it to come on automatically when the gun is cocked, or to stay put until engaged by the shooter. What a remarkable design! It also demonstrates the amount of trust Taiyo Juki had in their customers when the gun was made. I don’t think we’ll ever see something like this again, as long as the world continues to pursue its current litigious course.

Alan had to repair the rifle before shipping it, which gave him the opportunity to go inside. Since I’m in no way a qualified CO2 repairman, I stay out of the workings of gas guns; so I’ll use his description of what he saw. First, he says the bolt is adjustable for seating depth. Since the gun has a tight breech, this feature allows the shooter to adjust each specific brand and type of pellet to the best level of performance. If you think about it, though, you won’t want to be doing that much work all the time; so it’s best to settle on one pellet and then do the adjusting one time. I don’t know of too many other pellet rifles with this option; so, once again, the Taiyo repeater demonstrates its innovative design.

At the bulk-fill adapter, there are o-rings, instead of the more common flat seal. As a result, the bulk bottle doesn’t need to be screwed tight all the way before opening the valve. The o-rings catch and prevent gas loss by their design. Not a big deal, but it shows the level of attention that went into each small detail of the design. Alan found that a 3.5-oz. paintball tank could be left attached to the gun, giving many more shots than a single fill. Sort of like the Crosman CG rifles–reinvented.

He also reports that the gas valve is novel in that it has a two-piece valve stem and seal with a threaded stem, yet it’s the same size as the Crosman 160 valve assembly. The Crosman bulk-fill valve stem assemblies have threaded stems as well, but the 160 is a simple press fit that makes repair more difficult. Alan was able to cut and fit his own new seal because of this design, which not only made it possible for him to repair this rifle without a source of factory parts, but it also allowed the use of whatever hardness of seal material he wished to use.


The word “goofy” comes to mind when looking at the bolt handle. I’m sure the committee that designed it had their reasons.

Back outside the gun once again, the bolt handle also qualifies as a curiosity. It’s the most convoluted lever I’ve ever encountered. So strange is the shape that it gives rise to the suspicion it might be convertible from right- to left-hand operation. I have no way of proving that, of course; but if that isn’t the explanation, then a madman was loose in their design shop!


The magazine is long for only five shots; otherwise, it looks quite conventional.

The five-shot in-line magazine is conventional, in that it mimics others, like the earlier Crosman 118 and even the Crosman 400, somewhat. A slot through the left side of the receiver cover and the receiver block allows visual inspection of remaining ammunition. For safety’s sake, always remove these magazines before attempting any work on the gun, such as in the case of clearing a jammed pellet.


Here you can see the window that counts the pellets remaining. The button sticking up on the shaft under the bolt is for the variable safety.

Feeding was fairly smooth, although all these bolt-action repeaters with in-line magazines have little hang-ups sometimes. Even the Crosman 600 semi-automatic is known to occasionally catch pellets on the walls of the magazine. Only the Korean-built Career 707 lever-action rifle seems to have completely solved the problems of in-line feeding. I have never experienced a single hang-up in well over 10,000 shots with several 707s.

With the Taiyo repeater, however, it helps to develop a rhythm to the bolt–never going faster or slower than what the gun seems to demand. Do that, and you’ll have very few problems, as long as you use pellets the gun likes. Clearing a jam is a matter of removing the magazine and tilting the gun on its left side while fiddling with the bolt. Crosman 118 and 400 owners will be familiar with the drill.

I didn’t do a lot of accuracy testing; just enough to know that the gun falls into the very accurate category with others, like the Crosman 167 and 113. The reason I didn’t do more was the relative softness of the scope blocks and my desire to not injure them in any way. My scope was, therefore, mounted with great care not to bite into the soft metal. Screw holes at the front of the barrel suggest that open sights may have either been provided or were at least an option. The rear scope block would easily accommodate a nice sight of some sort–probably an aperture, which the accuracy of the gun surely warrants.

I was glad to have a chance to review this most unusual air rifle. Because it hasn’t really been imported to this country, it remains an exotic that only a few collectors can own; but it’s nice to know things like this exist. Certainly, it would provide a wonderful study of airgun innovation for domestic manufacturers.

Our thanks to Alan Becker for the loan of this unusual rifle.

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.

51 thoughts on “Taiyo Juki”

  1. E in V,

    Friday, October 23 12 noon to 7 pm and
    Saturday, October 24, 9 am to 5 pm.

    Roanoke Civic Center Exhibit Hall
    710 Williamson Road
    Roanoke, VA 24016

    Contact Fred Liady 540-989-5343

    email address frady45@cox.net

    The show flyer is now on the events page


  2. I just watched the video on the pistol hold. Very interesting. I was wondering while watching if the principles are applicable to the trigger hand on a rifle? The video made me realize that I may be gripping the rifle too much and inadvertently introducing a twist when I squeeze the trigger. A few weeks ago someone suggested that you put your thumb behind the trigger guard and pinch the trigger. I tried it, but my 94 was a little heavy to stabilize that way so it didn't work very well. The 92 is lighter and it did seem to work well for that (especially since the trigger is so heavy,) so perhaps this illustrates the point. Now I understand why and will look for a way to apply the principle to a heavier rifle.

  3. I think we're trying too hard on this corkscrew thing. If people say they can see a pellet corkscrew then it must be a large enough "diamter" to capture on "film". Just put a "cheap" high speed camera behind the shooter and "shoot". This should prove the existence of the "fact". Now, if you want to measure the actual diameter and striking point at each 10yd increment we might need a better camera.

    Sorry for all the " marks but they're right next to the "Enter" key on my keyboard and keep getting in the way.


  4. Volvo,
    Thanks for that answer to your gun storage. I knew I bought that MP-5 for some reason.

    Thanks for the PA site addresses on foam cases. There's one other site I found that says to just gather up all your foam cases and take them to the garbage dumpster.

    Yesterday I went to Gander Mtn to get a gun sock to see if it would be useful. I found one with their name on it, made in China, of course, for $10. It fits guns with or without scopes. When I opened it I was dubious about the scope part because it was only about 6" wide. However, it did stretch out to fit very tight over Ms. Marauder and her scope.

    Here are the particulars and maybe someone can tell me if this sock will really protect against rust (if I also use MP-5 as Volvo did).

    It is silicone treated.

    The uses stated (as printed exactly on the package) are:
    .Gun safe storage
    .Inside hard cases
    .Field case
    .Spare gun case

    Am I being misled by GM into thinking it's ok to store inside a case if it's inside this sock? Otherwise why use a sock?

    I know I should get a gun safe but I haven't, and having one delivered to my house will advertise to the whole neighborhood that I've got a lot of guns. I'd rather not advertise. I know that sounds paranoid and I don't think safe delivery companies will deliver at midnight.

    My concern is the gun getting dinged up, so the sock should provide some help there although the soft cases are doing a fantastic job on that score. I hang my guns up on a nail by the loops on the soft gun cases. This is working very well for my limited storage space.

    I guess I'm wondering if storing the gun in this silicone sock inside a soft case (Allen) is a good thing to do – or maybe I should just hang the gun up by the socks alone?


  5. Edith,
    Sorry…I meant to put this here on the current post:

    By rust prevention sack sold by PA, does that mean or include the silicone gun sock I mentioned earlier?

    Also, here is something interesting I found on the web:



    "Brownells has made gun storage even easier with their Triple Tough Rust-Blox Storage Kit. It consists of tough, flexible storage bags that are puncture resistant, semitransparent and have a 0-percent moisture transmission rating. Rust-protected items sealed inside will remain rust and corrosion free indefinitely. The sacks are resistant to all petroleum-based oils and solvents, and are non-biodegradable. They are so tough they will never break down, even in full contact with soil or moisture."


  6. CJr,

    Hanging your guns up by their socks alone gives new meaning to, "and their stockings were hung by the chimney with care in hopes…".

    My guns, for the most part are stored in a glass fronted, lockable, cabnet that I made from an old book case in the late 60's.

    The guns, until recently were wiped down with a rag sprayed with WD 40 after they were cleaned. The only problem I've ever had with rust was caused by leaving my Colt Woodsman Match Target in a foam lined hard case I made for the gun. DO NOT STORE YOUR GUNS IN FOAM LINED CASES.


    What an interesting gun. Thanks for pulling it out of your archives and sharing it with us. The tube mag sures gives its receiver a clean look which is more aesthetically pleasing to my eyes in comparison to any of the circular mags. I really like having the option of putting the safety on myself. I wonder if they made one that runs on air?

    Mr B.

  7. Edith:

    Thanks for your help with my unsatisfactory purchase of the .177 Desert Eagle pistol I spoke of yesterday. PyramydAir is living up to their high marks in Customer Service. I will know how well once the replacement pistol arrives tomorrow

    To Others:

    I saw these at CheaperThanDirt (http://www.cheaperthandirt.com/BAG198-1.html), and decided to go straight to the source and save money at:


    Like what I read, and Rick Dyer was able to answer all of my questions and add any other pertinent information. The number is on the website, and it might be worth a conversation with him for those that are interested. He tours gun shows with his product.

    Rick uses the same material that the U.S. Millitary uses to produce his bags. He has a nice selection of sizes.

    The Millitary's weapons go in and out of storage. The government replaces them every 5 years. You may get a longer shelf life if your guns are stored for extended durations without going in and out of them continuously, but at his prices I am protecting my guns at $20 per year over 5 years at the moment. If all seems well, I will be purchasing more.

  8. B.B.

    Interesting that the Japanese who pioneered airsoft as I understand have been relatively nonexistent in airgun manufacturing. They build good airsoft and good rifles like the Howa but no pellet guns.

    Thanks to all for your information about gun storage. My last act in a shooting session has been to snap the fasteners closed on my foam cases with a sense of satisfaction little suspecting the damage I was doing to my guns. Last night all the foam got removed from all the cases. As for a rust-prevention sack, what about plastic garbage bags? I sort of visualize the plastic keeping the moisture at bay. It wouldn't collect moisture would it? And what if the bag is not secured?

    Jane, congratulations on your S410 and glad that you enjoy all of your guns. You are really a fan of the high power. The kind of velocity loss that you get with a 6 shot magazine sounds like it would be death to accuracy at any distance. Do you really use a hand pump for your six shooters?

    BG_Farmer, the American Rifleman is a good source. I wouldn't have guessed that they have a lot of background in math, but with their credentials, I wouldn't expect that they would put up anything without a good basis. I didn't see glaring problems like in the website, but there were things I didn't understand. There was a chart at the bottom purporting to connect "imbalance factor" and group size for a given twist rate. Surely, a perfectly balanced bullet and a perfect bore would give you perfect accuracy for any twist rate. Once you start admitting any imperfections, how do you set boundaries on the minimum group size as the chart seems to be doing?

    As for the Gaussian distribution of shots in a group, the benefit for me is explaining why group size gets larger as shot number climbs up to 30 where it levels off. The Gaussian distribution suggests that larger shot numbers admit more outliers (larger standard deviations) up to 30 where the curve is pretty well established. Also important, I think, is that the Gaussian distribution does not apply to physical groups but to one's call radius which is an abstraction. For a tiny call radius like David Tubb, a group at a short distance would be one hole, but the Gaussian distribution is still operating. It's just that the area is so small that it's completely covered by the shots. Since numbers of shots seem like a clear case of repeated trials, I would think that the Gaussian distribution has to apply or there is something seriously wrong with the science of statistics.

    Herb, since a helix has axial symmetry you wouldn't need to place your cameras at different points around the axis. Just one will do. I pictured one camera with the resolution like those spy satellites although that's not feasible. An alternative is a row of cameras, but the alignment would have to be so exact, that this wouldn't be practical either.

    You've got me with the comment about time travelers and Pearl Harbor. I don't see what obstacle that poses to reading off spirals from sight corrections, although I'm not volunteering to compile them, so it is conjecture. I welcome the report of no spirals in the tissue paper experiment. 🙂


  9. I think Jane has given us the key to the spiral thing with her forensic suggestion and so did TwoTalon in talking about spiraling as an effect of a damaged muzzle. I disputed that prematurely. Any equipment short of perfection has to cause some wobble/precession and before the pellet flies off into complete instability, undoubtedly you will have spirals/helices that are fairly large. What then are the types of flaws that could produce spiraling? It could be anything. I mentioned to Clint Fowler the figure of 6000 rounds in a rifle barrel, and he said that such a barrel would be on the downside of use. Others would probably think their rifle was hitting its stride at that point. So any combination of equipment flaws, lighting conditions, and acute vision could produce sightings of spirals. By the same token, this may explain why you don't hear about this from the top shooters. Equipment like this would be long gone before it started behaving like this.

    As they say in Young Frankenstein: "If you change the pluses to minuses and minuses to pluses, Jane/TwoTalon, you've done it!"

    My only problem is with large spirals inches in diameter and sub MOA groups. These things seem divergent and basically incompatible. But otherwise, I think we have this settled in a gratifying display of bipartisan teamwork….


  10. Matt, Jane, CJr et al,

    Re: spiraling

    I'd agree Matt. It seems that putting our heads together we're sorted this out. In fact in the book "The Airgun from Trigger to Target" the Cardew's show a shadowgraph of a pellet, which has been tipped by a screw, exiting the muzzle with a considerable yaw. One can only assume that such a pellet would precess violently and probably spiral as well.

    RE: Gaussian distribution of shots in a group

    The group size gets "bigger" because you have a more statistically valid sample. a 3 shot "group" has a group size which can be artificially low.

    Let's just consider the horizontal error to make things a bit easier. When you measure the POI you're actually measuring two different things. the average horizontal error, and the standard deviation of the horizontal error. For a small sample size (number of shots) the average horizontal error gives repeatable values with very few shots. However to get a good measure of the group size (standard deviation of the horizontal error) you need a group size of about 30 shots. After about 30 shots you'd get a value which would be pretty stable if you increased the number of shots to 300 or 3000.

    Below 30 shots you should multiple the determined standard deviation (group size) by a correction factor which is based on the number of shots. the fudge factor increases the group size to an estimate of what the group size would be for an infinite number of shots.

    If I only take three shots within a group, then there is a considerable amount of luck as to how far apart (variable) the readings are. Let's take three measurements 50 times. For each group of three measurements I can calculate an average error and the standard deviation of the error. The average value for the three measurements will hover around some number (say 3/4 inch) very quickly. However the standard deviation will vary much much more. It is just a side effect of having a small number of shots in each group. However if I increase the group size to say thirty, the average gets somewhat more stable, but the measure standard deviation gets vastly more stable when I compare the measured values between the 50 measured values.

    Make sense?



  11. RE: Group size

    Think of a somewhat over simplified experiment. Let's roll dice.

    If I only roll two dice the changes of getting the same value on both dice is 1 in 6. I roll the dice ten times and pick my group size as the one time that a rolled doubles – double 5's. Oh, what a good shot am I.

    Now, instead of two dice, let's roll 30. What are my chances of getting all 5's? Not very good. The average is going to be 3.5 and the standard deviation something like 1.5. Now if I roll 300 dice or 3000 dice, I'll still get an average value of about 3.5 and a standard deviation of about 1.5.

    Does this help?


  12. When Herb mentioned Fournier Analysis', I started having nightmares about Dr. Wantagh and my course in electromagnetic fields and waves. Herb, so help me, if you get into Maxwell Taylor Series, I'm coming after you!!!

    The rest of you hosers, if you take the rifles out once per month and shoot them, the way we're supposed to, then wipe them down, you won't have to worry about rust no matter what case you store them in. 🙂


  13. Herb,
    Your examples makes sense the way you explained it. I don't remember where the number 30 came from for pellets, although we seemed to have locked in on that number, except I remember BB saying somewhere that 30 of his shots seemed to be enough for comparison. I myself have shot 30 and did not see a larger hole over 20. I have shot 20 and not seen a larger hole over 10. I haven't tried to see how often I can do this. BTW, Can we have one or two dice fall off the table to represent fliers?

  14. Fred,
    Thank you! thank you! so very much for your last comment on rust prevention! You have done much to squelch my anxiety over storage. I probably do take each gun out more than once a month but at least that much. I suppose if I was actually going to retire one of my guns forever I would use one of those norust bags.

    I was even thinking of storing the gun in a norust even for normal use to prevent internal moisture buildup that I can't reach with MP-5.


  15. Fred and CJr,

    Some people own more than a handful of guns, whether they be firearms or airguns. Some guns have been bought for the purpose shooting. Others guns have been bought for collecting, maybe for selling in the future, and the owner is attempting to limit its usage.
    I have over 50+ guns, and the collections of other that I know dwarfs mine.
    I have a handful of "go to" guns that are used regularly. They are in a safe, without cases, and allowed to breathe. The others are in other safes for prolonged periods of time, and protected.
    Any information about limiting rust for collectors like myself. The "hosers" as you call us. Edith herself mentioned the use of "rust-preventing" bags. I think this information is helpful those like myself.

  16. BB – nice video on shooting a pistol. I'll have to show it to some my friends. One of my friends was showing me how to shoot a .45 semi auto with a shorter grip. He shot it about the same way you did and he said that the bottom finger or two wasn't as important as people think.

  17. RE: Rust

    Maybe this is a situation where a synthetic stock is good. Wood contains moisture. Water in wood gets into air, then the water in the air could rust the steel. If the wood gets super dry then it might crack.

    It seems that the wooden and steel parts of a gun need different (ie the opposite) moisture levels.

    Would the best method be to remove the stock and store the metal parts in a sealed super dry environment? No water – no rust. The stock would then be stored in a humidor with maybe 25% relative humidity?


  18. Anonymous, I think your taking what Fred and CJr said a little to seriously. This is one of the things I have against the 'net…you can't see facial expressions and know when someone is gently ribbing (see Fred's smiley face at the end of his post).
    I'm a photographer by trade. I have a number of friends who have photo gear easily the equal of what I make my living with who take no more than a dozen pictures a year. I'll tease them about never using the gear but they know that it is just teasing. And I know that for some it's about taking the photo…for others it's about marvelling at the equipment.
    Just a thought.
    CowBoyStar Dad

  19. BB,
    I agree with ajvenom, that video on shooting a pistol was very helpful, although I haven't been able to try it out myself at the range, yet. I'm assuming your suggestions for a double action pistol carries over to a revolver as well. Don't see why not but I usually get in trouble assuming things.

    I tried dry firing my S&W .38 Special Airweight double action that way. It seems awkward, maybe because of the small hand grip, however, it does SEEM to stay on target that way. My middle finger seems to be too far below the web area of my hand to feel comfortable and there is no Beaver Tail to rest the web in.


  20. Matt & Herb,

    So you both now think bullets fly in helical patterns only as the result of gross abnormalities? Soon you can agree completely with me:).

    I think all bullets fly in helical patterns, because no rifle or bullet is absolutely perfect, nor is every rifle barrel, etc. I doubt the maker of Lilja barrels would have wasted time on an issue that only occurred with substandard barrels and projectiles. With all due respect to Clint Fowler, I don't think he's in the same league (nor does he pretend to be).

    The tolerances in the article are pretty tight, much better than you're likely to see on pellets, since the users he is addressing have to shoot one holers at 100 yards just to be competitive. Even with a perfect bullet, bore, etc., the bullet would still have a tilt for purposes of trajectory.

    I don't have a problem with the Guassian distribution of bullets in a group, just very little use for it in this context outside of characterizing group dispersion, since it doesn't tell me anything about what is causing the dispersion. Physics does.

  21. BG_Famer,

    RE: bullets fly in helical patterns ONLY as the result of gross abnormalities

    Not only, but that would be one cause. A really malformed pellet could also cause such a problem. A really poor fit in the bore. I'm sure there are numerous factors that could cause the problem.

    RE: Gaussian distribution of bullets in a group

    Unless you can directly measure some factor contributing to dispersion, you're left with statistical process control.

    (1) You measure group size.
    (2) Change something
    (3) Measure group size again

    If group size is smaller the change was good. If the group size is bigger, then the change is "bad" and you undo it.

    The point is that you also have to be able to trust your measurement of group size. What happens if you get "lucky" and shoot a smaller group size even though the change was actually detrimental?

    Let's say that you're shooting a group size of three, and testing a change which actually increases group size by 20%. There is a relatively large chance that the test group size will actually be smaller than the reference group size!

    This sort of sticky situation is why you need a working knowledge of statistics. Repeating the test, or shooting a larger group size of say 30, reduces the chance that such an error will occur.

    In fact I'd guess that virtually no error distributions are really absolutely Gaussian. It is just that Gaussian is "good enough." To determine that a particular error distribution isn't Gaussian you'd need a massive amount of data.

    For instance let's measure the muzzle velocity of a springer. Nominal velocity is 500 fps with a standard deviation of 20 fps. 30 standard deviations below the mean is -100 fps and 30 standard deviation above the mean is 1100 fps. Although I can't grasp how such a gun could suddenly shoot 1100 fps (maybe shooting into a vacuum?), the rifle surely couldn't shoot -100 fps (negative velocity of 100 fps). Yet for a true Gaussian distribution, the probabilities of the two results is the same. Since -100 fps is absolutely impossible, the muzzle velocity distribution can't be absolutely and purely Gaussian. It is just that assuming the Gaussian distribution works good enough for practical purposes.

    Physics can guide you as to what the factors are in the experiment, what factors are adjustable, and what factors are irrelevant. For example the color of your shirt shouldn't make any difference in group size.

    So absolutely. A knowledge of Physics is good too.


  22. Kevin:
    Thanks for the tip – just ordered some JSBs. Yes, the AAS410 is a 22-cal. Where do I find RC Machine? The AA clips are a (plastic) weakspot in an otherwise perfect rifle.

    Volvo: Yes, I've relegated the AA to avian invaders. I prefer to hit the larger critters with something more humane. To me, the 28g Eunjins are the minimum for groundhogs & gophers.

    Herb: The Blizzard & AA are very close in quietness. The Career is wool-packed, and a touch quieter. It's never been the report from the rifle that startles the prey – they move in response to me hitting the ground. Some birds will stay put for a second shot.

    Matt: Without adjusting, the Infinity drops a full inch in 6 shots at 50 yards. (The Blizzard almost as much). I dial the power up with each shot, and by now can empty the clip and stay within 15FPS – no shift in POI. Yes, I do use a pump. It's a royal pain, and hence I only take a few shots each day, (when I see something invading)..

    Best regards,

    Jane Hansen

  23. CJr,

    I'm in a quandry and would like your advice, please. I've qot a Talon SS in .22 along with a .22 24" barrel and AirHog Bloop Tubes for each. I love the gun and how adjustable it is. HPA or CO2. Back yard to 100 yards.

    I like the Marauder, but what will it do that I cann't already do, except its 10 shot option? Would you compare and contrast your SS and Ms. M? If one had to go, which and why?

    I guess I'm trying to either justfy the cost for a new toy that I really want or decide that the toy isn't for me. Thanks alot sir.

    Mr B.

  24. Matt61:

    You mentioned – "…As for a rust-prevention sack, what about plastic garbage bags? I sort of visualize the plastic keeping the moisture at bay. It wouldn't collect moisture would it? And what if the bag is not secured?"

    Plastic garbage bags would actually trap moisture in the bag, and would be much, much worse.

    Take a look at this page from the NoRustBag website comparing their bags with regular bags:


    Hope the information was useful for those interested.

  25. The goofy bolt handle looks like a fine cost cutting solution. It forms a perfect (looking anyway) thumb hook. No need for an expensive large ball on the end.

    I like it from a design perspective. But from a pure looks perspective it could be more graceful.

  26. Herb,
    I don't disagree with you on the statistics, and the method you propose is certainly a valid method. However, it does seem to me that a good (and no more complicated than necessary) physical model of a bullet in flight would be of extremely high value in determining what parameters to tweak.

    As an aside, I still think we're conflating 2 extremes. 1) helical path that defines group size. 2) exaggerated helical path that results from gross abnormality or perhaps adverse environmental conditions.

    If you read the article that I referenced, you saw that even small imperfections in bullets or twist rate can cause relatively large changes in group size. These imperfections are not, however, abnormally large, but in fact quite normal and unavoidable.

    The article also has a formula for calculating the minimum group size based on rifling rate and bullet "imbalance" There is reference to an earlier article in American Rifleman (presumably when it was still worth reading) that derived this simplified formula from a more complex one. As a start I would like to find a librarian who could get a copy of the 1965 American Rifleman article referenced in the Lilja article (that's a hint to Matt:)).

  27. BB,
    I've been trying to decide all day (in the midst of some actual work:)) how I feel about this rifle, and I'm still confused:). It was definitely worth a write-up. Its styling (not to mention features like the power select) is certainly out of the box and unmistakably Japanese from several decades ago.

    "The Schimel Man" reference threw me. I thought about Schimmel (which I seem to recall in reference to a less ornate rifle), but a search turned up a reference to this blog, explaining that its an obscure brand of pistol.

    Anyway, thought I'd try an on-topic post, but not ask any questions, since I know you're busy:). I hope to get a gold star from Kevin for search function use:).

  28. BG_Farmer,

    I'd agree with your comments. No doubt precession and spiraling form some sort of continuum. The precession can be so small as to be undetectable, or so bad that it causes a large spiral.

    I would point out also that the American Rifleman article is about bullets, not diabolo pellets.

    I enjoy theorizing and fiddle around too much with theory. Practically there are a finite number of parameters which can be manipulated. For instance rifling rate is an very interesting concept, but you can't go to Wally-Mart and buy a dozen barrels with different twist rates.

    I'd guess that a variable twist rate would be best. The skirt on a pellet is rather fragile and a high twist rate would rip the skirt off.

    By and large, it seem that the best advice is really to try as many pellets as you can and pick the ones that shoot the best. I just don't think that the theory is capable of analyzing the different factors and picking all the right parameters based on the theory. Riflemen have been playing with this for hundreds of years, and ammo selection is still more art than science. But yacking is fun, and I do learn more about ballistics.


  29. DesertEagler and all rust advisors, thanks. I have a no rust bag on order. If I didn't live in such a dry climate I would be screwed.

    BG_Farmer, I think helical paths can be of any size. I guess what I object to is huge helices and small groups, so I tie the degree of abnormality to the size of the spiral.

    Actually, Clint Fowler is a High Master who has placed as high as number 6 at Camp Perry in the high power matches, has won the Nathan Hale Trophy twice, and has shot on teams in international competition with David Tubb (whom he said he did not pose any threat to). He's a world-class shooter who should be in the same league as the Lilija barrel makers. His shooting record in combination with his gunsmithing is why I went with him. Anyway, the point I was drawing from his comment was different standards of abnormality which had to do with my question about the Lilija site.

    What exactly does their chart measure? Perfection of bullet and bore should mean no expansion in group size. So, what degree of imperfection are they using to assign minimum group sizes to twist rates?

    Assuming that they are talking about spiral pathways, I take their data as tentative support that helices can be very small relative to group size. 🙂

    The value of the Gaussian distribution for group size is to assess the value of groups composed of varying numbers of shots as Herb has laid out, and it gives some meaning to outliers. But you're right that it's not of much practical value in solving problems. I'm on my professional mettle and will look into your reference.

    Herb, I agree with your explanation of the Gaussian distribution. That leaves the final cloud on the horizon for this issue. Is the average of 6 five shot groups (as one often finds in magazines) as reliable as one 30 shot group? I say no.


  30. Matt,

    RE: "Is the average of 6 five shot groups (as one often finds in magazines) as reliable as one 30 shot group? I say no. …"

    I mostly agree. If you have 6 five shot groups you have a mean and a standard deviation for each group. This diminishes the overall degrees of freedom of the sample. Thus if you take an average over the 6 groups, the overall "average" group size isn't based on a sample size of 30 but something like 26 or 27. Same thing with the "average" standard deviation. You "pay" for all the calculated values.

    But have 6 five shots groups allows to to use other statistical techniques. For example let's assume that the 6 groups are all shot on different days. Now you can test for day to day variations which you couldn't do with one big 30 shot group.

    Or assuming that you shoot groups sequentially, is there a variation between groups? Think of a PCP and the power curve. If the first group has valve lock it will be worse than the good groups that follow. But the last shots may also have velocity dropping off rapidly. So they could be worse too.

    So when you talk about "as reliable" you have to be very careful to define what criteria are being used to determine "reliability."

    Statistics is just weird. It twists back onto itself in all sorts of funny ways.


  31. Jane Hansen,

    Completely agree with your comments about the AA S410. The factory magazine is astrocious in an otherwise fine gun. I think Air Arms built the gun and the government supplied the magazines.

    Hope your gun likes the jsb 15.8 gr (in a little wind) and jsb 18 gr (in even more wind) as much as mine does.

    Here's a link to the aftermarket magazines that are really great:



  32. Herb,
    "Continuum" is perfect. I agree pellets and bullets are somewhat different — the real question is how fast should pellets spin to get some benefit (they are drag stabilized after all) without increasing the group size, I think. You can actually select various twists for c/f (and some .22) rifle barrels, but I think your point is still valid; its not easy for a pellet rifle.

    At one point, based on what BB told me of the history of pellet rifling, I conjectured that pellet rifles had simply adapted the standard rimfire rifling rates without much thought. Its probably good enough, but perhaps a slower or faster one would be better, especially since the range of pellets is so much farther now with technical advances. Just thinking…always dangerous:). Pleasure yacking with you.

    First, I think my comments about Clint Fowler were wrong in expression, although not in intent. I just meant he is certainly no more an authority on barrels for benchrest than Daniel Lilja, although he certainly may be more knowledgable in other areas (no basis for judgement).

    As best I can tell from the article, the value used for imbalance in the twist rate chart is .000084" (84 millioneths of an inch).

    I still share your trepidation in the big spiral, small group case, lest there be the need to add endless epicycles and the like in the manner of the later Ptolemaic system:).

    If (professional goad) you can find the article, that would be great:)!

  33. Mr. B,
    I like the Marauder better because it has a nice stock instead of the round tank. I get a better feel as a rifle. I also think the M is more accurate. More later gotta go.


  34. Chuck,

    I took my double-action revolver training from Ed McGivern, who wrote the book, "Fast and Fancy — The Book of Revolver Shooting"". McGivern set several world records for speed and accuracy in the 1930s, some of which still stand. Elmer Keith defers to McGivern when it comes to double-action revolver shooting.

    I also shot an S&W model 37 Airweight snubbie that didn't fit my hand. The triggerguard beat hell out of my middle finger during recoil, though double-action was the only way to control the gun. May I recommend a Makarov pistol instead? There is less recoil and far more accuracy without any pain.

    I have switched to the Micro Desert Eagle as a carry gun. I will soon make a report on it here in the blog, but first it had to go back to Magnum Research for some reliability tweaking.


  35. CJr,

    Gotta agree with you on the looks of the Marauder verses the Talon SS.

    However, I'm skeptical on the accuracy of Ms M verses the SS. How much of a difference in group size are you getting, at what distance and what settings for the SS. Remember I haven't shot the Marauder, but my SS will give me one hole groups at 20 when I do my part.

    Mr B.

  36. BB,
    I feel more comfortable with a revolver. There is less likelihood that I will shoot myself and it is easier to clean, plus I don't have to worry about a safety, which is usually on the wrong side for me unless I find an ambidextrous one.

    I've have been eyeing pistols whenever I visit a gun counter and when I decide to get one I'll put the Makarov at the top of my list. I really trust your recommendations. What caliber do you recommend for home defense at 10ft-10yds?

    I like the compactness and light weight of the Airweight and it fits nicely in my jeans pockets, front or back and I think the .38 +P will do ok for in house intruders. Not much fun for plinking or target but practice we must.

    Mr B,
    I shoot airguns 99% 10m indoors.
    Putting the benefits of the mag aside:

    I have used only CO2 in my SS and it is a .177. I have never shot it out doors or farther than 10m. I get around low to mid 600fps with CP 10.5gr on CO2. It was my most accurate and fun gun until Ms. M. The SS's only detractor is the bottle for a stock. It's harder to get a consistent shoulder mount but that is by no means a show stopper. There are aftermarket shoulder gizmos that can be put on the bottle to make it more stock like but, in my opinion, the maker charges way too much moolah.

    Ms. M is a .22 and I'm using HP air. I get around high 800's to low 900's with CP 14.3gr. So, any comparison between the two isn't apples to apples. I wanted to enter the .22 world so I chose the Marauder to do that. The main detractor, but at the same time a plus, is the plastic magazine. But again this is no show stopper. The magazine does not affect accuracy in any way.

    I fault the Marauder magazine because, while the one that came with the gun is working fine, a second one I ordered from PA is defective and I can't load pellets into it. I've been trying to call tech support and customer support last night and this morning but can't seem get someone to pickup.

    I will join the rest of you on your concern about the durability of the magazine. I can see what's going wrong with the new magazine but I can't do anything about it. Also, I've noticed debris collecting inside the orig mag. It can't be disassembled for cleaning so I'm not sure what to do about that.

    Please don't think I'm bad mouthing the Marauder because of this magazine. It's not a perfect world and this is a very minor issue. All other aspects of the M make it a super gun in my experience.

    I will say if I could keep only one gun I would keep Ms. M. but I like them both very much. The Talon SS is like Sigourney Weaver in Aliens where Ms. M is like Ingrid Bergman in Casablanca but with a little more attitude.


  37. The Roanoke, Virginia, "International Airgun Expo" is this weekend. Hard to find anything on the internet about it, but it's on the billboard outside the Roanoke Civic Center. Anyone going, or is this even worth going to?

  38. Jay,

    Only if you like airguns! Roanoke is the largest, richest and most exciting airgun show in the world. But to the untrained eye it looks small and sleepy.

    I saw a $50,000 Girandoni military repeater sell there for $3,500 a few years ago.

    If you do decide to drop in, look my up. My name is Tom Gaylord.


  39. Great – I've found your writeups from past years, but very little about this coming show. I hope to be able to stop by after work Friday.

    My eye is certainly untrained – I only discovered "adult" airguns this fall, and your blog has been an invaluable resource. I'll look for you.


  40. Jay,

    Definitely come by on Friday, but also try to be there Saturday, as well. Friday you will see all the collectors from all over the world who have flown in. On Saturday, the locals (within 400 miles) drive in to sell their relatively new airguns. It's a different show.


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