Why don’t they design pellets to go supersonic?

by B.B. Pelletier

Whenever I write about the fundamentals of shooting, it usually starts a good discussion. The CB cap vs pellet rifle article spawned an article about why we like to keep airgun velocities under the transonic/supersonic level for the best accuracy, and THAT, in turn, evoked this thoughtful question on the Pyramyd Air facebook page last week:

“This may be a dumb question — but, since the issues revolves around the ‘badminton birdy’ design of our current air rifle pellets. Has there been any attempts to change the design to provide stable flight, and maintain more energy, at faster speeds? Just curious….”

That is not a dumb question at all! In fact, it’s such a good and thoughtful question that I thought it deserved a special report because we’re seeing a rise in the number of firearm shooters who are reading this blog. Just like airgunners, those who shoot firearms come with different levels of experience; and some of them are not attuned to the fundamentals of accuracy. They buy commercial or military surplus (milsurp) ammo and just shoot it without appreciating how much better they might do with a little tweaking.

The same can be said of airgunners, many of whom have bought into the high-velocity craze without realizing (or perhaps caring) all they are giving away. Today, I want to look at the projectile we shoot — the common pellet — with the hope that, by understanding its design and limitations, we can extract the best our airguns have to offer.

The diabolo pellet
Diabolo (pronounced dēˈabəˌlō). According to the dictionary, the origin of the word comes from a toy top that was popular in parts of Europe. It was also sometimes used in juggling performances. The word came from 20th century Italian from the ecclesiastical Latin diabolus, which means devil; the game was formerly called devil on two sticks.

The diabolo pellet is characterized by a pinched or wasp waist and a flared hollow tail or skirt. Though there are many different variations on this central theme, they all have these characteristics.


The diabolo pellet can have different nose shapes, but all of them have a pinched waist and a flared hollow tail. The center of mass is biased forward by the hollow tail.

The design of the pellet biases the center of mass forward of the center point, like a throwing dart. The flared skirt and to a lesser extent the pinched waist create high drag that keeps the pellet oriented forward in flight.

History
I wish I could say exactly when the diabolo pellet was first introduced, but I’ve been unable to find a source that gives a definitive date. Nor is there a George Diabolo after whom the pellet is named. What I can say at this time is that it didn’t exist in the 1880s but was already in existence when the first modern air rifle — the Lincoln Jefferies underlever made by BSA — was offered in 1905. That’s as close as I’ve been able to pin down the date of introduction. I would welcome any information that contradicts my dating or offers greater insight.

When the diabolo pellet was first sold, most airguns were smoothbores whose designs were already many decades old. Buglespanners, the underlever guns that cock via the triggerguard, were being made in calibers as small as .22 as early as the 1850s, though that caliber is rare. By the mid-1870s, a great many companies were selling smallbore airguns in many calibers.

Perhaps the most well-known and prolific of these, at least in the United States, is the Quackenbush company, whose proprietary .21-caliber long guns and pistols sold for a tenth the price of handmade gallery airguns from just a decade before. Quackenbush guns and the others like the Gem, Haviland and Gunn, and others all used darts and something called cat slugs (sorry, Edith) that were nothing more than cylindrical lead slugs of bore diameter. They were very short, so they either avoided the tendency to tumble or it didn’t matter that much. Another variation of the cat slug was the felted slug, which was a cat slug with a short wad of felt clued to the base to provide drag.

Once the diabolo pellet came on the scene, it quickly rose to the top of the sales heap, surpassing all other projectiles. It did so because its high-drag design stabilized the flight of the pellet without requiring a rifling-induced spin. However, spinning the pellets did much to improve their accuracy, and the new BSA spring guns could not have hit the market at a better time.

Where the other types of projectiles were inaccurate at distances beyond 30 feet (excepting some handmade darts that were extremely accurate and had been in existence for over a century, but required specialized and expensive dart guns), the new diabolos pushed out the distance to 60 feet, where they gave one-inch, five-shot groups. In that day, being able to group like that was like saying a modern PCP can group an inch at 200 yards. It was an unthinkable distance that revitalized airgunning like nothing before.

Diabolos and the accuracy barrier
Certainly, up to this point in time (1905), there had never been any thought given to airgun projectiles going faster than about 500 f.p.s.; and only that fast in very few guns in the smallest caliber (No. 1 bore, which is also called .177). Velocity was not important, as the airgun was seen as an extension of the gallery target gun — though one that was much less expensive and more available to the common man. Accuracy was the sole purpose for the diabolo until the mid-1920s, when the Crosman Corporation started selling a hunting-themed pneumatic (Power Without Powder).

Power/velocity in airguns crept up very slowly throughout the 1920s and ’30s, and accuracy did the same. What held back accuracy was not the barrels of the guns, some of which were very fine, but the quality of the pellets. Airguns had run into the “accuracy barrier” because the manufacturing processes hadn’t reached the levels they would several decades later. It wasn’t until after World War II that European pellet makers finally started making really accurate diabolo pellets.

Sheridan shows us the way
In fact, there’s an anecdote in all of this; because in 1947, the Sheridan company decided to not use a true diabolo design and instead created a proprietary cylindrical pellet that had no pinched waist but did still have an open tail. The tail was not flared; instead, it had a tiny stepped ring of lead that was slightly larger than the diameter of the rest of the pellet and that was what was engraved by the rifling when the pellet was loaded.


The vintage Sheridan cylindrical pellet was not a true diabolo, but it had high drag just the same.

The reason given for this departure was that there was no accurate .22 pellet available. That may have been the truth, because the first prototype Sheridan rifles were created in .22 caliber; though, when brought to market, they came in a proprietary .20 caliber that has been the same ever since.

The first Sheridan pellet was a throwback to the schuetzen rifle days when all lead bullets were made with bases that were a couple thousandths larger than the rest of the bullet. These bases sealed the bore against the hot gasses at firing, and they also made it possible for the shooters to load the bullets separately into the rifled bore ahead of the cartridge case. This prevented the bullet from tipping as it entered the bore, because it was already seated there by hand.

The one or two lead rings at the base of the bullet were relatively easy to engrave with the rifling, as opposed to trying to engrave the entire bullet. That was the mistake that British and German pellet makers made when they tried to make the solid pellets (which I’ll discuss in a moment).

The sound barrier is breached!
Until the 1980s, peak pellet velocities remained below about 870 f.p.s. In the early ’80s, several rifles finally achieved 1,000 f.p.s. Soon after that, British airgun designer Ivan Hancock broke the sound barrier with his Mach I breakbarrel springer that got over 1,150 f.p.s. in .177 caliber. After that, things changed very fast.

Suddenly, accuracy was out the window, as shooters discovered that the diabolo shape is not well-suited to flight in the transonic or supersonic region. The fact that the pellet remains at this high velocity for only a few yards makes no difference. The damage was done. The extreme buffeting caused when the pellet reaches and passes transonic speed, then slows back down and goes through it again is more than enough to destabilize it and cause groups to open.

Sales go crazy!
However, the other side of the coin is that high velocity sells guns. A company that advertises their gun shoots 1,000 f.p.s. and higher attracts lots of attention and, yes, sales. In fact, so much attention has been given to 1,000 f.p.s. that it is now seen as the marketing kiss of death to advertise anything less. Some companies have gone to great lengths to tout ever-higher velocities without a thought being given to accuracy. Special lightweight, lead-free pellets are now selling well partly because of the velocity boost they give to the guns that shoot them.

Which brings us back to the initial question
If the diabolo design doesn’t work at high velocity, and we know unequivocally that it doesn’t, then why doesn’t someone design a pellet that can exceed the sound barrier? Well, to a very limited extent and with disastrous results, it has been done. The so-called “solid pellet” was the first attempt to do this. This projectile is really a bullet — not a pellet, and as such is brings all its bullet weaknesses with it. The first is that nobody can load a lead bullet into the bore of a rifled gun unless he’s Superman. Those who shoot muzzleloaders know that it takes a device called a short starter and often a separate mallet to force the bullet into the rifling of a bore.


These .22-caliber Eley solid pellets weigh 30 grains and require the shooter to engrave the rifling at loading. They failed because they’re too difficult to load and because they’re inaccurate in most airguns. Other designs were similar and have had the same problems.

So, no solid pellet currently on the market can be loaded into an airgun easily enough to use. If it could, the second problem crops up. The twist rate of the rifling is too slow to stabilize a solid pellet. That twist rate, which is very often one turn in 16 inches of travel, was taken from the .22 long rifle cartridge when the first modern air rifle was made. It hasn’t changed since then. It works with diabolos, but not with solid pellets because they’re too heavy for the lower velocity at which most airguns can propel them. They have no additional means of stabilization and need to be driven faster to stabilize. Being both very heavy and also having a lot of friction with the bore, they go much slower in any given airgun.

Okay, make the airguns more powerful
About seven years ago, I could see where all of this was heading, so I tested these pellets extensively in an AirForce Condor — the only air rifle I can afford that can get them up to 1,000 f.p.s. You know what? They still aren’t accurate. They’re stabilized at that speed, but they still shoot in 5-inch groups at 50 yards, while diabolos going less than 950 f.p.s. will group in three-quarters of an inch from the same gun.

Okay, then why don’t “they” make a more powerful air rifle that can shoot these things really fast?

Stop right there!
Don’t you see where this is heading? When an AirForce Condor shoots a 30-grain solid “pellet” at 1,000 f.p.s., it isn’t an air rifle anymore. It has become a firearm in all ways except how it’s powered. The Condor can shoot a 30-grain diabolo that leaves the muzzle at 1,000 f.p.s. and probably kill a woodchuck at 75 yards with ease, yet it still won’t travel downrange any farther than about 500-600 yards max. The high drag of the diabolo design slows the pellet after a very short time, but a solid pellet leaving the muzzle of the same gun at the same velocity will go a mile and a half. It has nothing to slow it down. We’ve then turned the Condor into a .22 short.

There’s an airgun maker in the Netherlands that makes custom .25-caliber rifles that can shoot 60-grain jacketed boattail spitzer bullets at over 1,200 f.p.s. That’s very admirable for an airgun, but that rifle, my friends, is a .25-20 Winchester in all ways but the name. Maybe not the modern loading of the cartridge, but it’s certainly close to the original loading. So, while it can actually be done, I’m saying that it shouldn’t be. Turning an air rifle into a firearm is just asking for more legislation that we don’t need.

Now, before some of you go off on big-bore airguns, they’re just as relatively safe as smallbore airguns. They shoot about as far as shotguns shooting rifled slugs, and most states that worry about distance limits for sporting guns allow the shotgun with slugs.

It’s not the power of the gun at the muzzle, but how far downrange it throws the projectile that makes it more or less safe. And, with diabolo pellets, airgunners have achieved something truly remarkable — a safer bullet.

I hope this report sheds some light on today’s state of airgun technology.

83 thoughts on “Why don’t they design pellets to go supersonic?

  1. B.B.,
    This report is another one of those jewels that is worth bookmarking, like the one on trigger placement, and others. PA should point to reports like this in their ammo section. Nowhere else are you going to find the meat of this particular issue in a single place like this.
    Thanks,
    Victor


    • Victor,

      Thanks. I wanted this one to be a lasting report, so I wrote it that way. I have proposed that we also put this one into the articles section, where it will remain visible for much longer.

      B.B.


    • I was thinking the same thing, it’s a good idea to keep it as an article. Same thing with the single mother teaching her kids to shoot if it isn’t already there.

      J-F


  2. twotalon,
    The issue that I was having with wild groups was probably 99% the fault of that one really bad tin. I measured the wild group today at 3.5 inches wide. I took that same rifle, changed the rings and scope, and went to another tin of pellets, and was able to put 15 shots in a 3/8″ group. I then went back to that bad tin, and the group opened up again just like before. As I mentioned last time, some pellets dropped right on, some required a little effort, and some required a lot of effort to push them in.

    I decided to sort them into three groups; very loose, not too loose not too snug, and too snug. After sorting, I only shot the ones that were too snug. Again, the rifle was already sighted in for the previous tin, which shot very well. Shooting only the very snug pellets, I formed a pretty tight group about 2.75″ down and to the right of the bulls-eye. I think that even within that group of very tight pellets, there was too much variation. For the most part, they cut a continuous vertical line of just over half an inch.

    I still attribute some of the wildness to the set of rings that I was using. I hadn’t noticed, until I removed the scope, that those rings had no sticky tape. It’s bad enough that they only had a single pair of screws, but not having tape had to hurt a little. Thanks for your valuable insights. You did mention that you’ve run into a bad tin like I did. I’ve never had such a bad tin of .22 CPHP’s!

    Victor


    • Victor..

      You have to watch those pellets for a lot of reasons. Mac already showed us that a difference in fit changes impact point.
      Crosman pellets are hard. This may make them the worst choice in some rifles when there is too much variability in size. We are not considering weight here, just size. There can be weight variability between pellets of the same size, and size variability between pellets of the same weight.

      You can usually get away with a little variability (snug to tight) with a rifle in which the pellet is actually seated into the bore (including skirt) better than you can with rifles that you only seat the head in (springers).
      With springers (or rams), the developed pressure curve has a lot to do with pellet fit. Not just the head, but the skirt too. The pressure curve has to rise to the point that the skirt end of the pellet is finally forced into the bore. At this point you have pellet inertia and friction balancing against the pressure curve. This is a short, high impulse curve that has to work right with the pellet to give you any kind of consistency. The pressure curve is affected to a great extent by the pellet used.

      A softer pellet may be more forgiving than a hard one when there is variability in fit. Softer pellets will be easier to drive into the bore, so small variations in fit will not be as noticeable with them.

      I found that shooting the AA 4.51 and 4.52 pellets in one of my HWs gave me a surprise. Between the two tins, I could not tell the difference in fit by feel. Both were just snug, but one shot much better than the other. The rifle could tell the difference and did not like one of them. Really it did not like either very well, but the one was much worse. There was also a distinct difference showing on the chrono.

      Then there are pellets that look pretty consistent on the chrono, but don’t shoot for crap, and others that don’t shoot very consistent on the chrono that shoot pretty good. I am guessing that as long as a pellet is about right to get a good pressure curve out of the rifle that it will shoot OK …under some circumstances. So much interraction.

      So how tight should a pellet fit? Loose head is bad. Too tight of a head is bad. What about skirt thickness and size? What is just right? Whatever the rifle thinks. It is always good to find several kinds of pellets that a gun likes, at least pretty well. If it is so touchy that it can only live with one kind then you might find yourself in a jam some day when there is a change in the pellets .

      twotalon


      • twotalon and Victor,

        I can attest to the importance of the seal from the skirt on springers. When I get a tin of my favorite H&N FTT pellets (for my Quest 800) that does not shoot as well as most, I have found that they usually have greater variability in velocity when fired over the chrony. Experimenting has shown that I can greatly increase the consistency of the velocity of pellets by ever so slightly “flaring” the skirt by a very small amount. This inevitably tightens up the groups. I don’t even break out the chrony anymore – when a new tin is not as good, I set it aside to fix it later, and after I flare them, they usually shoot fine. I have had tins where this tightened up the velocity spread from about 650-690 fps to 690-705, just like the best tins do on their own.

        All it takes to flare them is the ball end of the Beeman pellet seating tool. Just place it in the skirt and give a slight twist under a little pressure and it opens them up just at enough. I even made a simple holder jig with a bit of wood and 1/4″ bit – drop in a load of pellets and touch them up fine.

        By the way, I found this dose not work as well with the harder Crosman pellets – they don’t seem to flare uniformly like the softer H&Ns do, and they end up lopsided. It can help with sealing and thus velocity, but it pretty much trashes accuracy on them.

        Alan in MI


        • Twotalon, Alan,
          This is the first time that I’ve experienced such a horrible tin. I think this just shows my lack of experience with these things. But as could be expected, if you sort the tight ones, they form a decent group. The loosest ones are all over the place (also to be expected). Again, this awful mix generated a shotgun pattern that spanned 3.5 “. This was a 20 yards. At 10 meters, I’ve shot single, but ragged, size groups. I’ve found my particular Titan to be very accurate. That’s what shocked me so much.
          Victor


    • Victor this post has me wondering if it is possible to just get a ‘bad tin’?
      I’ve regaled all of you too many times with my efforts to wring some decent long range accuracy out of my Slavia.
      I had tried a number of pellet types and 1.25-1.5″ was the best I could seem to do at 30yds (10 shot groups).
      I opened up my second tin of JSB Exacts this Saturday. I had finished the first tin I tried a week or so ago and had come to the conclusion that this would likely be the pellet I would end up using…grouping 1-1.25″…okay, but still frustrating with what everyone says my combo (Slavia 631+Hawke AO scope) should produce.
      Well, the first 10 shots went into a group about .75″.
      The second group the same and the third group about .5″.
      I honestly don’t think I did anything different…and the wind was no less/more than usual.
      But all of a sudden I have an accurate gun ;-)


      • CowBoyStar Dad,
        This was a shock to me, because my Titan has proven to be VERY accurate. YES, each tin is different, and some can be extremely bad. Logically, this might also imply that some tins are exceptionally good. I guess this is why competitors sort their pellets.

        My first thoughts were that there was something wrong with the gun, the scope, the rings, me, or all of the above. I had been laid out for a couple months because of a bad back, so I hadn’t shot anything until very recently since early June. I did, in fact, need to work on my skill a bit, but even that didn’t explain what should have been an inch size group, worse case, being 3.5 inches.

        We know that every gun is different, and we know that every tin of a particular kind of pellet is different, let along different types of pellets or different types of guns. With that, on any particular set of shooting sessions, there’s a bit of luck involved with respect to the absolute performance that we experience during those sessions.

        Victor


  3. BB,

    I am inclined to go with what I know works. So pellets like H & N and RWS target pellets for accuracy
    as well as the more accurate JSB’s. For hunting, predators, CHP (in guns which shoot them accurately) and others like RWS Superdomes and the boxed domed crosman in both .177 and .22.

    Most of the lightweight alloys are not accurate in most guns so I don’t mess with them much except to chrono them for bragging rights.

    I will not even try any of the novelty “pellet bullets” which are supposed to be accurate at high velocity. Until I see repeatable accuracy reports on those the sellers can just keep them!

    So, “it is what it is”, and I will stick with what I KNOW IS accurate!

    Cause if I can’t hit my target, nothing else matters!


  4. I’m with Victor. This is a really great article. And the logic is compelling. You don’t want to drive a modern pellet supersonic, and if you had pellet and gun that worked well together supersonic, it would change the airgun game for the much worse. Let’s not go there.

    People always want to reduce the quality of products (whether a TV, stereo, airgun or car — or anything else) to a single figure of merit that the sales department can tout as making Brand X/Model A better than Brand Y/Model B. Remember the stereo power wars of the 60s-80s, or the horsepower battles. Muzzle velocity seems to be the curse of the airgun marketeers. I wish it were something else like c-t-c accuracy. The old Beeman catalogs used to list the accuracy with every gun, and I thought that was a pretty good gauge of quality. The speed of a pellet that misses its target is irrelevant!

    Even in the US it is hard enough to keep airguns essentially available and essentially unregulated. I don’t want to tempt fate.

    Thanks, BB, for today’s contribution.


  5. In book “BELL TARGET SHOOTING” which is evidently available as a PDF file at:
    http://www.targetbunny.btik.com/attachments/Bell_Target_Story.pdf

    What is really interesting is on page 21 of the PDF file. It clearly shows a box diabolo pellets made by of Cox and Son’s pellets with a date of 1902. So it would seem the diabolo was created some time between 1890 and 1902. so that shaves a few years off the latest date.

    Image only…
    http://www.localhistory.scit.wlv.ac.uk/articles/belltarget/bell19ax.jpg


  6. In our earlier exchange I threw out the question whether there were lessons to be taken from the 22lr target projectiles to make an accurate high velocity pellet. While my thoughts were not on taking as literally a transplanted projectile as was done in the experiments described above, I did appreciate reading about the efforts.

    What I actually wonder is if just the some relevant design elements of the 22lr projectile might be adapted to the high power air guns without need to cross the threshold into firearms type power. Elements such as the ogive, and a cylindrical bourrelet, while keeping a hollow base. To overcome in-bore friction, would driving bands such as is now used in copper and bronze solids help, or would a less severe pinch on the wasp waisted diabolo allow for low in-bore drag, while at the same time providing better aerodynamic stability at or over mach 1?

    Has the Sheridan design been a failure at high velocities as well? Has anyone played with these?
    http://www.corbins.com/pellets.htm


    • Chris,

      Yes, .22 caliber heeled bullets have been used in air rifles.

      Although many airgunners refer to them as “bullet heads” and “bullet head tips” Eley actually sold their .22-caliber heeled bullets for the Daystate AirRanger that was purported to reach over 100 foot-pounds of energy. That was later revised back to 80 foot-pounds and I don’t know if there was really a change or someone just decided to actually chronograph the rifle. You see it had an 18-inch barrel and I told the importer when I saw it that it could never get 100 foot-pounds with a barrel that short.

      Accuracy? The crickets are still chirping.

      The AirRanger at 50 foot-pounds with a barrel sized properly for airgun pellets, however, is quite accurate.

      B.B.


  7. At the same time as I bought my B3,I needed a tin of pellets.
    Looking through the top of the glass cabinet I spy the .22 Eley solid pellets you mentioned.
    “Got a get me some of those” I thought.
    After I got home then I read the words in small letters.
    ‘FAC rated rifles only’
    Never mind.
    Loading was a bit of a struggle but thanks to my B3 having an oversize bore it was possible.
    (No way would they have fit my HW)
    The first shot was at an old wooden gate at about 15ft.
    I don’t know where the pellet went.It cleared the barrel but that is about all I know.
    More or less after that I gave up on them and sold them to a buddy for a knock off price.
    Dave



  8. BB,
    Thanks for this brain-tickler of a blog. I have always been intrigued by the self -imposed “usable” velocity limitation placed on airguns by the diablo pellet, even though I realize that supersonic speeds have only become a possibility in the last 10 or 15 years. I also find it ironic that the small caliber airguns that can achieve supersonic velocities, are limited mainly to the diablo pellets, and that big bores, which cannot easily achieve supersonic velocity, shoot conventionally shaped bullets which might actually work at high vel.
    BB, I hear what you are saying about airguns becoming just like powder burners if suitable small caliber bullets were developed and followed through on. But that is a philosophical argument rather than one of technology. I tend to agree with Chris about a blend of air and powder design elements. Frankly, with the way velocity sells, I am VERY surprised that one of the speed merchant airgun companies has not come up with a high speed pellet/bullet that actually works.
    In my opinion, the smooth sided swaged bullets are useless, just like the PBA pellets, and something with 2 or 3 narrow drive bands (like the Nosler .357) in a small caliber would be a good starting point…IF…a useful and usable supersonic airgun was desired. But that puts it back to the philosophical discussion.
    Honestly, within the next several years, I expect to see a small caliber airgun “bullet” that works. B.B., like you, I don’t particularly care for that idea, but for better or worse, would you care to venture a prediction on whether that might happen?
    Thanks,
    Lloyd


    • Lloyd,

      I designed a pellet (bullet) that will work at supersonic speed, but the pellet maker I was dealing with had loose lips and the idea was stolen and knocked off. I won’t say who did it, but my design is being produced today. I haven’t tested it and frankly I don’t want to, because I am pretty sure that it works, if they followed all the design guidelines.

      B.B.


      • BB,
        A very unfortunate series of events that can happen in the blink of an eye. If they stuck right with your design, I bet the pellet/bullet turned out pretty darn good.
        Lloyd


      • This is outrageous. I’m reminded of a book by David Baldacci. An enormous 7 foot tall criminal is standing over one of his henchman, covered in gold chains, who is lying sprawled at his feet. “Know what my biggest problem is?,” says the criminal, replacing the safety on his Beretta. “Finding reliable help.” This problem appears wherever you turn.

        Matt61


  9. Need for Speed aka Velocity crazed Americans and their airguns.

    I really like these types of recent articles by B.B. Have to admire a guy that is single-handedly trying to turn this tide in American air gunning.

    I’m proud to be an American. In my view, there are a lot of examples where culturally we still act like teenagers. Maybe a lot of this attitude is because we’re such a young country. 235 years old vs. 2000 years old. IMHO our insatiable appetite for ultimate velocity in airguns whether it’s making a more powerful gun or a pellet that is revolutionary in design is an example of our teenage mentality. The need for speed.

    I can’t help but think about our air gun friends around the world, that frequently contribute here, and the velocity (Foot Pounds of Energy, FPE) limits that they are restricted to and are enforced by their laws. This power limitation has bred a culture of air gunners that have learned it’s more important to hit their target every time than it is to wing a pellet at 1200fps and rarely hit your target. Poor misguided souls.

    The 12 foot pound limit in the UK has not limited the number of air gun hunters and air gun target shooters. Their consistent, winning performances in the World Field Target championships is testimony.

    I don’t think our lust for power in air guns will wane anytime soon but when someone asks me for my recommendation for their first, adult air gun purchase I almost always suggest one that is under 12fpe. My motivation is that I want them to be able to hit their target and have a fun shooting session without wearing themselves out.

    kevin

    ps-This is no way implies that I feel that anyone, anywhere in the USA should legislate or restrict power in air guns.


    • Kevin,

      You said it all when you noted that the UK does quite well at under 12 foot-pounds. They have many more serious airgunners than we do, though I suspect that we have more who own airguns but view them as toys.

      The point is, you don’t need to go supersonic to have fun. And if you want to, there are plenty of rimfires that will do it just fine. My current favorite is the .17 HM2.

      B.B.


      • B.B.,

        Which gun(s) are you shooting .17HM2 ammo out of? Do you have a conversion for your 10/22?

        I’ve been considering a conversion for mine but the history of the 5mm still lingers and I’m not sure if the added expense of ammo is justified. Is the .17HM2 gonna last? Care to push me over the brink?

        kevin


        • Kevin,

          I was shooting a custom-made .17 HM2 that was based on a Mossberg 42 and one that was based on a Hungarian single-shot. With the Mossberg that was scoped I shot a 0.629″ 10-shot group at 100 yards. With the Hungarian rifle that had Redfield target sights I only managed one-inch groups at 50 yards, but Mac shot a 50-yarder that went into about 3/8-inch last week.

          I’m having a Mossberg 42 custom built for myself at this time. What a wonderful gun it turns out to be!

          B.B.


          • B.B.,

            “0.629″ 10-shot group at 100 yards”. Okay, you have my full attention.

            One last question if you don’t mind.

            The last two summers I’ve been shooting the rimfires a lot. Every weekend with rare exception. A little over a month ago I had “one of those days” when there wasn’t any wind and I shot several sub 1/2″ groups with the 513T with a bushnell 7-21×40 and wolf match target ammo (40gr., 1050fps) at 100 yards. Next weekend I couldn’t shoot a group smaller than 3 inches. Scope problems. Sent it in to Bushnell for repair. Took my 6.5-20 leupold custom scope up to the cabin and mounted it on the 513T. Shot it on Friday in about 10-15mph gusting wind and couldn’t do better than 2 inch groups while trying to shoot between gusts. Took the gun back to the cabin and cleaned the barrel. Shot it on Saturday, in less wind, and my best 10 shot groups at 100 yards were about an inch. I even checked all the screws on the gun. Last year I would have been happy but this year I’m not.

            In your experience, is the lighter but faster .17HM2 less affected by wind than subsonic .22 LR?

            kevin


            • Kevin,

              I would have bet against it, but yes, I think the .17 HM2 is less affected by the wind because of its velocity. That group I told you about wasn’t the only one, either. The owner of the rifle has about ten targets like that at both 50 and 100 yards. He called today to tell me he is finishing the first stages of my new rifle and I will have it out to the range this week for it’s first test-fire. But we have both noticed that these new .17 barrels need at least 100 shots through them before they start grouping that well.

              I will keep you posted.

              B.B.


              • But we have both noticed that these new .17 barrels need at least 100 shots through them before they start grouping that well.

                <sigh>

                Guess that means I need to run at least another box through my .17HMR before trying to really zero the scope…

                Off course, there is also the matter of which round do I zero for… the hollow point, polymer-tip, or heavier game point…

                Wonder if I can afford a range run after my upcoming lay-off (not so much the ammo/range cost, but the time I should be boxing books and porcelain).


    • Kevin,

      I feel sometimes we are too harsh on newcomers that simply don’t know any better. If they have a firearms back ground, it is pretty common knowledge that faster means a flatter trajectory, longer usable range, and more energy at the target without really any limits – at least until you reach the “barrel burners”. In the newbies mind, maybe he compares a .223 to a .22-250. They just don’t understand the limitations of the pellets design, and that is not really their fault. If we want to be harsh, it is the manufactures that deserve to be whipped for taking advantage of the general public.

      As far as limits in other countries, my first puppy was a mutt named Lad. His father was a large German Shepard named Mud, as he loved to role in it – and his mother a beautiful Collie. Bought from a farm in the 1960s he was a dogs dog. I could share stories of him, but time doesn’t permit. Suffice to say, Lassie had nothing on him.

      Five years latter when we moved from my small country town, I learned our home in the city would not have an out building from him to sleep in. My father took him to a friends farm where he stayed behind. He would make the 10 mile trip home twice before we actually moved, so they chained him up.
      My replacement came from the then new shopping mall. A Pekingese. That dog was the equivalent of what it must be like to own an R1 that shoots at less than 500 ft per second.

      Sure you can grow to like it, but it will never be the same.

      What happened to Lad? The farmers prized male German Shepard tormented the chained dog, but got too close to my beloved friend. Lad tore both his ears off and mauled him nearly to death. They shot Lad.


      • Volvo,

        Sure hope my comments read by newcomers to air guns aren’t taken as “harsh” but rather enlightening. Never ceases to amaze me how many guns and how much money most airgunners spend to end up with a smooth shooting, accurate, medium powered spring gun or ram.

        Your dog analogy is a good one.

        Guess I should be shot for the perception that I’m chwing the ears off new airgunners.

        Hope you’re well and business is brisk.

        kevin


        • Kevin,

          Knowing that I usually own the harsh category, I cannot judge another. But calling shooters “velocity crazed” and “teenagers” just doesn’t seem like the friendly handshake and warm smile you are known for. It just struck me as, well, Volvo like.

          Don’t worry however, if the powers that be decide to shoot you I will insist they use only airsoft and allow you a running start. You may also pick the shooter. I’d suggest Slinging Lead, I have a feeling you may escape unscathed. Now that feels better, all is right with the world.

          As far as business it remains fair, on the home front we found out my youngest daughter needs the same surgery my middle daughter had a couple years ago. We got the news the morning after the .25 cal Marauder arrived, hence its short stay.


          • Volvo,

            I see your point. I get a pass since I was once one of these velocity crazed spring airgunners and am on a mission to help other newbies avoid the same pitfalls. I’m not optimistic since in my instance I had to experience the gamut.

            So sorry to hear about your youngest. Seems only the strong are tested in this manner. My prayers of healing for her and strength for you have been sent.

            kevin




        • Matt61,

          Yes it was. I would never on known, but overheard my Dad telling my Mom. Not sure which was best – knowing the truth, or just imagining he was fine. My kids think the Pekingese I got at the age of 11 was my first dog, for them I decided the story is better left untold.


    • That must be the one and only good thing about our dumb 500fps law.
      If it wasn’t for it I would probably would have went for a 1000fps monster like you and so many other and probably would have been happy with the groups I was able to achieve because I wouldn’t have known any better. After a while the rifle would have went in the downstairs gun cabinet (that’s where the guns I don’t shoot end up) because mainly of the force required to cock them and the recoil they send back to you.
      Don’t get me wrong I would buy a Marauder rifle and pistol tomorrow if there was a change in the law (not taking the shroud thing into the equation), same thing if Crosman came out with a 500 fps model.

      Every rifle I own shoots under 500fps and even if I could I probably wouldn’t buy any 1000fps rifles, not springers anyway. Right now one of the rifle I’m using the most is a small Slavia 618, it’s so easy to cock and shoot, you literally could do it all day, I couldn’t shoot a squirrel with it but no soda can is safe!
      That thing is just so much fun to plink with, it’s missing the rear sights (they broke during shipping on it’s way to me) yet I haven’t missed a can between 30 and 45 feet (depending if I’m shooting from inside the house or on the edge of my 15 feet deck) with it using only the front post.

      J-F




    • Bobby

      If I tried that, I would end up wrapped up like a mummy but in string, with two sticks and a couple of diabolos bulging out here and there. It would be like Charlie Brown and his kite.

      Thanks for the link.


  10. Nothing at all wrong with more more power, folks just need to get it in the proper manner. That means increasing the size and the weight of the projectile while staying in the sweet spot for velocity.

    The R1 was probably the first mass made air rifle to show case this trait. Sticking to old school theories when I bought mine I stayed with .177 caliber as .22 was thought to be the caliber of the uneducated. Accuracy with that R1 was best with one of the heavier .177 pellets of the day. Keep in mind the Internet is but a novelty at the time, and Chrony’s are mostly for the professionals still.

    When my R1 book arrived in the mail I quickly realized through the vast experience of Tom Gaylord that this rifle did have the ability to make use of .22 caliber pellets. Oops.
    I quickly traded my Beeman P1 for a new .22 caliber barrel assembly and was up and running with more use-able power.

    The best way for a novice to understand this would be to look at the specifications for a typical PCP offered in 3 calibers. Normally you will find .177 will be about 24 ft lbs, .22 about 34 ft lbs and .25 at around 45 ft lbs.

    So if you want more power, go with size and weight, not speed – assuming the platform can handle it.


  11. RE: “I feel the need for speed”

    There is another aspect to this. It isn’t just the projectile. You also must consider the power-plant. A PCP will just be able to get over the speed of sound with a light projectile which means that in a short distance that the projectile will drop back into the trans-sonic region.

    A PCP is ultimately limited by the RMS velocity of the gas which is about 1640 fps at room temperature. Of course if you charge with neon or helium you could propel the projectile faster. For an reasonable empirical equation of a PCP see:
    http://www.network54.com/Forum/79537/thread/1226513246/1226699539

    A high power springer could go faster, but a high power springer is very hold sensitive. A springer can shoot faster than a PCP since the air is heated when it is compressed.

    Regards,
    Herb


    • Herb,

      I have to disagree that a springer can go faster than a PCP. In several years of testing the limits the fastest springer I have witnessed went about 1,425 f.p.s. Get them to detonate and they do go faster, but they aren’t airguns any longer.

      By contrast, I have seen a PCP get up to 1,486 f.p.s.

      B.B.


      • BB,

        I’m sorry that I wasn’t clearer. I was not trying to compare “real” airguns, but the theoretical limits. The point that I was trying to make was simply that a springer could theoretically be faster than a PCP. The springer not only compresses the air but also heats it. So the gas in a springer is a lot hotter than ambient. The hotter the gas, the faster the molecules in the gas move.

        Regards,
        Herb


    • Herb,
      I still have a little trouble accepting that the maximum velocity is constrained as concisely as described in that thread. I am sure the math is fine, but I am not sure of the derivation of the constant, 172. I assume it is a reduction of other constants. It also assumes a constant force on the pellet, when in reality, there will be a decreasing force as the air in the reservoir expands into a larger volume. There is also the assumption that the mass of the column of air behind the pellet is moving at the same speed as the pellet, which may not be the case. The pressure drop at the breech (orifice in a flat plate) also is relevant.

      All that said, the main reason I have reservations is that using that formula, I have actually achieved the theoretical maximum calculated for a 2800 psi shot. Back in early 2008, I made a video, for which I have previously posted a link on this blog, where I shot a number of “max velocity” shots through a .25 cal 24″ long barrel using different weight pellets at different velocities. The applicable shot was 21.6 gn, 24″ barrel, 2800 psi, velocity 1354fps. The really bizarre thing is that if you use the formula you have cited, the calculated max velocity also is 1354 fps; exactly what I shot. (please check my math!) So, if you make deductions for pressure drop from the reservoir, pellet break-away force, barrel friction, etc., my velocity should have been less than the theoretical 1354 fps velocity, but in fact was not.

      Using the method of calculation I normally use, the maximum MV would be about 1520fps, but again, taking no friction losses into account. That is still below the 1640 theo max.

      I really cannot offer a good explanation. I will try and re-post the video link this evening.
      I hope that makes some sense.
      Lloyd


      • Llyod,

        It is an EMPIRICAL formula not one based on theoretical soundness. It seems to account for pellet mass fairly well.

        For a massless pellet the maximum velocity is the RMS velocity of the gas. In other words, all the air molecules move down barrel at exactly the same speed, and without bumping into each other. This is the real limit.

        The only way to get the molecules to move faster is to heat the gas, or to use a lighter gas such as neon or helium.

        Herb


        • Herb,
          I agree that two ways to get a higher max velocity out of a PCP are with a heated air or with a lighter gas. Room temperature air is fairly limited in its performance.
          The formula cited from the other forum may be empirical, but I do believe it is backed with good theory. The guy is pretty sharp.
          Have you ever heard, or better yet, seen any data from someone using helium (please guys, the inert gas for kids balloons) to achieve higher velocities? It’s RMS velocity is about 4,400 fps, and besides the down side of leaking, I wonder if a normal set-up might show a velocity increase? Just curious.
          Lloyd


          • Lloyd,

            When I worked at AirForce we had a customer who converted a Condor to run directly from a helium tank. He claimed to be getting over 1,500 f.p.s. with 15.9-grain JSB domes and was shooting groups at 200 yards. So he claimed.

            B.B.


            • That’s a darn nice claim if he can back it up. Hmmmmm….
              And a very Happy Birthday to you BB, and many more to come!
              Lloyd


          • Llyod,

            I seem to remember a couple of discussions about helium on the yellow. Helium would definitely yield a faster muzzle velocity. But once out of the barrel, the pellet is in air again.

            I really don’t helium would be practical without major modifications to the gun/rifle. First helium leaks a lot more as you noted. Then I think that you would really need to redo all fittings to cut down on leakage. Also helium flows more freely than air. So you’d probably need to play with valve and transfer port to optimize the setup for helium.

            Regards,
            Herb


      • First I want to wish Tom a happy birthday! May you have many more to come!

        Secondly I’m with Lloyd on this one, someone on the CanadianAirgunForum using only an already shot RWS hyper velocity pellet casing
        http://new.pyramydair.com/s/p/RWS_Hyper_Velocity_22_Cal_11_Grains_Pointed_Lead_Free_100ct/526
        that weighted 1.4gr at 1734 fps. He used an already shot casing because otherwise it didn’t grab the rifling.
        Have a look at his tread here : http://www.airgunforum.ca/forums/topic39117.html

        J-F


        • JF,

          We’ll just have to agree to disagree since neither of us can account for all the experimental conditions.

          The 1640 fps is an experimental limit based on room temperature. As I remember the temperature assumed was about 20 Celsius or about 70 Fahrenheit. This is an absolute limit based on gas thermodynamics.

          So to get something faster, something about the experiment is not as it seems. You just can’t cheat thermodynamics.

          Regards,
          Herb


          • I didn’t conduct the experiment or witness it personnaly, I’m merely reporting what I saw posted and I have no reason to doubt his result as he hasn’t much to gain from it.
            I don’t know if you looked at the link or not, he also mentions he tried with a cleaning pellet and got 1400fps readings, maybe someone who has a Talon and felt pellets could try it? It would give us an idea regarding his results and if they are bogus or not.

            I know your math is right and I’m far from being a mathematician but according to math bumblebees can’t fly.

            I wish he had filmed it instead of just taking pics.

            J-F



  12. B.B.,

    Congratulations on a really great article! I think this is one of your very best.

    High velocity without accuracy is pretty meaningless in value.

    I think you touched briefly on an important point that is worth further discussion. It is possible to produce air rifles that are virtually firearms in short-range performance. For someone who might not care about shooting air guns, it is simpler (in this country, anyway) and cheaper to just buy a .22 firearm.

    I see a potential problem with air guns that can duplicate limited-range performance of firearms. You implied that overlapping performance of air guns/firearms could lead to regulation of air guns as firearms. This is what has happened in Canada and the UK.

    There is a danger of the reverse happening, too, in this country. Air guns are specifically exempted by Federal Law from being defined as firearms. This is usually interpreted to mean that air guns are not restricted in the manner firearms are here.

    But firearms are protected even though they are regulated. They are protected by the Second Amendment. US citizens have a Constitutional right to own firearms. This is a right, not a privilege granted at the largesse of government.

    Because air guns are, by definition and law, not firearms, they and the people who own/use them are not protected by the guarantees that apply to firearms. By Federal Law, a big-bore Sumatra air rifle and a Daisy Red Ryder are the same. Consequently, there are localities where American citizens are not allowed to buy or own air guns. There are also ridiculous laws like that in New Jersey where the police get to “make sure your air gun is safe” (read “play with at the police station”) before you get to possess it.

    If air guns were to “cross the line” based on performance rather than construction, and be considered as firearms, they would then have to be allowed the protection given all other firearms. Right now, they have no protection under the law.

    Les


  13. One of the reasons I still shoot airguns is because they aren’t as powerful as firearms. They work great around the house with little noise or cost. They also do what they are supposed to very very well. Of course they are great fun to shoot. What’s not to love!

    Mike


  14. Why would a top be named for a devil? Is it because it spins in a wild and berserk way–sort of like the Tasmanian devil cartoon character?

    B.B., how do you know all this stuff? I don’t believe there are authoritative histories of airgunning. Did you do archival research? It sounds like you were present at all the events. According to my research, it is your birthday. Yes? If so, happy birthday, and thanks for all you do (even if it’s not your birthday).

    Firearms are to airguns as a broadsword to a rapier!

    I hope no one on the East Coast was affected by Hurricane Irene. Overhyped or not, it seems like it did significant damage.

    Flobert, I thought that TV comment was extremely funny.

    Slinging Lead, actually I think Tonya Harding was real class material who had a legitimate shot at the gold, and that makes it all the stranger for her to try to sabotage Nancy Kerrigan like that. She was just out-of-control, gun moll as world-class figure skater.

    Okay gents and ladies, I have emerged from the weekend a new man. I have reloaded cartridges and a new Arsenal of Democracy is open. Perhaps you were wondering why I have been quiet all this time since I announced that I was ready. (Maybe you weren’t wondering at all.) It turned out that I wasn’t quite ready and have been busy. I could not figure out how to open the plastic box with my reloading dies. Picture a smooth two-piece box with no obvious latch or means to secure it whose top simply would not come off. I wondered if there was suction holding it in. Well, I’m gentle with equipment to a fault. But finally there was nothing for it, but to get my Ka Bar and try out the hammer built into the butt by smashing the box open. Worked like a charm with absolutely no marks of any kind on the knife. (This is the second great performance by that knife. While practicing to shift to a reverse grip I accidentally dropped it point first onto an ammo can from which it bounced up a considerable distance before falling to the ground. That point is like a needle and I braced to see damage, but there was none whatsoever. Amazing.) Once I got the dies out, I realized that I did not have a shellholder for the press.

    But one by one, these problems were solved and the time came. Here my luck changed because none other than B.B. paid me a quick visit on Skype to look over my set-up and answer a few questions. Is that cool or what! So, you see I am a prophet after all. It’s just like that Star Trek episode I referenced where Dr. McCoy is trying to reattach Spock’s brain to his body while Spock guides him through the process.

    Spock: Now seal the nerve with the tri-laser connector.

    McCoy (muttering): Tri-laser connector.

    Wayne, this goes out to you. You must cross over and give this a try. With your experience using tools and business acumen, you’ll be producing top quality ammunition in no time and enjoy doing it. I myself can see the possibilities now. A bullet seating depth gauge to find the exact overall length of a cartridge in a given chamber, a straight-line bullet seater, hand-trickling in powder to the exact tenth of a grain all because…with Matt61 reloading we WILL make it right.

    Matt61


  15. Happy Birthday B.B.!

    Hope you get presents by the Gaylord! Did you know “Gaylord” is the nickname for those huge cardboard boxes that fit on a pallet? At least some are made by a company called Gaylord.

    I think of pellets like little badminton birds. Badminton is a game that goes way back, older than tennis I believe. And it was long known that the high-drag design makes the birds fly really fast then drop off quickly in velocity. Badminton is an extremely high-performance sport, tennis is much more about sheer power. I’m sure someone figured out that if you make a pellet that has a high velocity initially but drops to a harmless level rather quickly, you’d have something you could shoot fairly safely in a back yard etc. without it being a danger at long distances. This is why I’ll shoot up at a squirrel etc in a tree but would never think of it using a .22 rimfire.


  16. BB,
    I was thinking ?? maybe the smooth bore with a dart wasn’t to far off . It seems to work pretty well for the smooth bore cannon on the Abrams tank. Years ago, probably in Popular Science, I read where they were using an air gun to fire flechtettes to test aerodynamics , It was powered by a piston driven by an explosive charge to compress the air. I don’t remember the velocities that were achieved but they were really high.



      • B.B.,
        When I worked on SDI back in the 80′s, my company was developing Kinetic Energy Weapons (KEW’s – rail guns) whose velocities, at that time were classified. In any case, they said that at those ultra high speeds, the metal projectile acted as a liquid, including the metal that it hit.
        Victor



  17. B.B.,

    A very HAPPY BIRTHDAY wish for you sir.

    A great article that all air gunners need to read. I for one like to be able to live in the city and shoot in my back yard without being visited by the SWAT team. I can buy a suppressed .22 rifle for less than a PCP with a carbon fiber tank, but I sure cant shoot it in my back yard.

    Volvo is exactly right in saying go to heavier projectiles for more power. I think black powder instead of smokeless powder when I’m looking for more power.

    Bruce


  18. B.B.
    That may well have been what I saw. Boy 10,000 fps and a 98 ft barrel every ones going to want one of those. That should group pretty well at 30 meters. Does Gammo know about this ??
    And a very happy birthday to you and many more.


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