Why you DON’T want to break the sound barrier

by B.B. Pelletier

This report has been done in bits and pieces many times over the years, but I’m putting it together today because of a surge of new airgunners coming online. Many of them are older firearm shooters, but many others are younger shooters with no real background in the shooting sports. We’re seeing an upturn of fundamental questions in our social networks and through customer service representatives that tell us that this topic needs to be emphasized once again.

What’s wrong with the sound barrier?
The sound barrier is a lot more familiar to people of my generation, because it was being talked about and always in the news when I was a youngster in the 1950s. Young folks don’t think much about it these days because supersonic flight is a foregone conclusion; but back in the 1940s, it hadn’t yet been achieved by a manned aircraft in level flight. A couple pilots inadvertently broke the barrier in dives from high altitude during World War II when they were testing certain fighter aircraft, and one of them was Cass S. Hough, the grandson of the founder of Daisy and later a president of the firm himself. At the time, he was trying to solve a control surface problem with the twin-engined P38 Lightning fighter, so he took one to over 40,000 feet, nosed it over into a steep dive and might have become the first man to ever break the barrier in an airplane. I say “might” because almost every air force of that period has a similar story. There’s a plaque in England that commemorates that flight in 1943, but I’m sure there must be other plaques in other countries, as well.

Before I hear from all the engineers (except the aeronautical engineers) that a prop-driven plane cannot go supersonic because the propeller has to break the sound barrier long before the aircraft does, it is possible — when gravity assists the aircraft — for a prop-driven plane to go supersonic. It’s not a good thing. As Hough discovered, the subsonic control surfaces no longer work right at supersonic speeds, but it can be done. As a result of Hough’s flight, the P38 received a special “dive flap” control to help free the controls when the speed got too high.

The problem with the sound barrier is what happens as you approach it and then pass through. In short, a pressure wave of air builds in front of whatever is moving that fast. Normally, this pressure would then flow around the surfaces of the aircraft and be left behind — but at transonic speed, the air compresses and develops eddies and currents that play havoc with the control surfaces of the aircraft. The surfaces that work well up to a certain subsonic speed start to act odd when they reach the transonic speed, which is about Mach 0.9, or nine-tenths of the speed of sound in the conditions of the moment.

One bad effect of reaching the sound barrier is a buffeting that causes the entire aircraft (or pellet) to vibrate. Aeronautical engineers had to learn to design aircraft for supersonic flight while maintaining the ability to fly at subsonic speeds as well.

Now, let’s talk about pellets
Pellets don’t have adjustable control surfaces. They are what they are, so they like to fly at certain speeds, and in all cases with standard diabolo pellets (wasp-waisted with a hollow tail) that speed is subsonic. In fact, even the transonic region is bad since it’s the place where the buffeting starts.

Why we don’t want 1,000 f.p.s.
This is why we do not want to shoot pellets at 1,000 f.p.s. Because 1,000 f.p.s. is always in the transonic region.

How fast is the sound barrier?
The answer is: it depends. Things that change the speed of sound are the elevation above sea level, the ambient temperature and humidity. Elevation is subtle, because it also influences the air temperature. Temperature of the air is the most influential factor that affects the speed of sound, and I’ve learned that where I live the barrier can exist anywhere from about 1,060 f.p.s. and above. The usual speed of sound is given as about 1,125 f.p.s. when all conditions are “normal.”

You know the pellet has exceeded the sound barrier when you hear a sustained crack with the shot that cannot be attributed to the muzzle blast. Silenced firearms dramatically show off this sustained crack because the bullet is quiet at the muzzle and then returns an indistinct sound like distant thunder as it goes downrange.

But, it isn’t the sound that airgunners should be concerned with. It’s the accuracy, or rather the lack of it that is caused by the buffeting mentioned earlier.

How pellets are stabilized
Pellets are stabilized both by spin and drag. Since they are hollow, they are light for their length, so the spin can be slower than for solid conical bullets. That’s why solid pellets are usually a failure.

But pellets are also stabilized by high drag, just like darts. The wide hollow skirt creates a low-pressure area behind the pellet that drags on them as they fly forward. It keeps the point oriented forward and stabilizes the projectile in flight.

At subsonic velocities, pellets are usually stabilized pretty well; when they get up into the transonic region, they’ll flutter in flight, just like those older airplanes did. And, those flutters translate into larger groups. Knowledgeable airgunners like to keep their velocities under 900 f.p.s. for safety’s sake.

One additional reason to stay below the transonic region
I was chatting with Mac about this; and we’ve both observed that in spring guns, the faster they shoot the twitchier they are as far as hold sensitivity. That has nothing to do with the sound barrier — it’s just a fact of life for spring guns. Throw in the breakbarrel design that’s also very hold sensitive and you have a real recipe for disaster. Yet when you look at all the magnum airguns that are being sold on the basis of velocity, the majority of them are breakbarrels.

So, we have a bad situation in which the most inexperienced shooters are drawn to the very airguns that are the most difficult to shoot on the basis of two things — the advertised velocity and the low cost! It’s like a church that decides to hold its meetings in the piano bar of a casino.

I’m on what, I guess, is a lifelong crusade to spread the word about airgunning so people don’t come in the wrong doors and find things amiss. I want to give each new shooter the same chance I had to discover the shooting sports on the very best terms. If they could just see a fraction of what I see, I know that many of them would be intrigued enough to stay and grow our hobby.

Airgunning can be fun and very satisfying if you do it the right way. The right way is to shoot enjoyable guns that hit their targets more often than not. Hyper-velocity airguns are the antithesis of that. They are the .338 Lapua Magnums whose owners have each fired one box of ammo before giving up on the beast.

116 Responses to “Why you DON’T want to break the sound barrier”

  • The Big Bore Addict Says:

    Hey B.B.

    I’ve heard that if you take an airplane that’s NOT designed for supersonic speeds, & you put it in a nose dive to achieve breaking the sound barrier, that when you do, the flight controls will reverse.

    Have you heard of this?

    TheBBA

    • flobert Says:

      Yeah I’ve heard that too and I’m not sure where I’ve heard it but it might have been in the book, “The Right Stuff”, talking about Yaeger’s tries at it?

    • B.B. Pelletier Says:

      BBA,

      No, I didn’t hear that, but the controls did freeze on the P38, which was what LTC Hough was testing when he made that flight.

      B.B.

      • Matt61 Says:

        So once the controls freeze on you, how do you recover and survive since gravity will keep pushing you to go faster? I’ve never figured that out–unless the vibration of the plane somehow slows it down if it doesn’t shake itself apart.

        Matt61

        • Wulfraed Says:

          One of the things that may happen on “normal” planes (non-swept wings) is that the air flow “detaches” from the control surfaces — they are basically in vacuum, hence no effect. Over the transition speed there are also trailing shock waves from the rear edge of the wings, etc.

          Googling indicates that the P-38 main wing loses lift, and the tail section sudden gains lift, which pushes the plane even steeper. That might be the “control reversal” mentioned.

          Normal dive brakes are a wall — they induce a massive slow down effect. The P-38 solution was an under wing unit whose purpose was to redevelop/maintain lift on the main wing, and reduce the tail lift effect. (Though I could swear the P-38 also had traditional dive brakes on the top of the nacelles).

        • B.B. Pelletier Says:

          Matt,

          Hough wrote that he actually stood on the controls until they gave way the tiniest bit, which was all he needed to fly out of the dive. The plane had already killed several less experienced pilots by that time.

          B.B.

    • Bobby Nations Says:

      BBA,

      I don’t know about whether they will reverse or not, but they will go wonky in other ways. BB calls it freezing, which is an adequate term. In truth, they simply stop working for the most part because the airflow over the wing completely changes as you leave subsonic flight on your way to supersonic. Designs that work well in the subsonic region are sub-optimal for flying in transonic and supersonic regions.

      The real problem for an airplane not designed for subsonic flight is that the pressure spikes caused as the bow or shock wave passes across the aircraft (i.e. the transonic region) to establish itself behind the aircraft (i.e. the supersonic boom) is that the airframe itself isn’t designed to handle the often enormous and erratic pressures that result. Many of the early and inadvertent planes that passed through the transonic region simply disintegrated in mid-flight. Even planes designed for these effects could come apart in flight as well. In fact, that is exactly what happened to Geoffrey de Havilland, Jr, son of the founder of de Havilland aircraft in Britain when testing one of the early British attempts to break the sound barrier in level flight.

      As the D.H.108 approached Mach 0.9, its structure began to fail sending the plane out of control. The aircraft broke up and its debris rained down upon Egypt Bay.

    • Fordum Says:

      The control reversal idea came from a British movie about breaking the sound barrier. No one had ever done it for sure and survived, so they needed a gimmick to explain how the fictional British pilot was able to do it and survive.
      All the pilots who had done it accidentally or come close reported problems with the controls. So some bright director came up with the idea that maybe the controls reversed when you got that fast.
      At the time the movie came out Yeager was within days of doing it for real, or had already done it.
      His success was kept top secret for a long time because we wanted to be the only country that could build supersonic planes.

      So, as a result, the silly movie became everybody’s idea of how it was done. A few years later, someone, maybe the president, asked Yeager at a function honoring him if it was true that the controls reversed when you went supersonic.

      He said flatly, “anybody who reverses the controls at the sound barrier is dead.”

      If I remember right, the movie name was “Breaking the Sound Barrier”

      I was close. Here is a link. http://en.wikipedia.org/wiki/The_Sound_Barrier

      • The Big Bore Addict Says:

        All very interesting info guys.

        Fordum,

        Thanks for clarifying that. I’ve been flying R/C planes on & off for over 20 years, & it didn’t sound possible to me, but of course none of my R/C’s ever went Mach 1. I do have an F-15 that was clocked with a radar gun at 137 mph though. I mostly enjoy doing aerobatics. My F-15 doesn’t allow for much of that, but it does fly & feel like the real plane, & those 137 mph passes inverted at 6″ above the runway are a real crowd pleaser. I’m in the process of selling all my gas/nitro etc., R/C’s & going all electric. Vegas has grown so much that to get to a field where I can fly my gas planes, if you don’t plan to make a day out of it, it’s just not worth the time. Electric has advanced so much now, that you can still have some pretty fast & powerful planes, get some decent flight times out of them. Also they’re a lot less work & a lot less to carry. With electric, if I want to go fly for just an hour or two, I can just go to the park or even a big parking lot, & still have a lot of fun.

        Speaking of… Hey B.B. have you had a chance to fly that helicopter yet?

        TheBBA

  • flobert Says:

    BB this reminds me of Federal’s Gold Medal .22 program, I mean the real stuff with the indented base. It edges into the transonic, and I don’t think anyone actually took it to the Olympics, although the .22 silhouette guys liked it for its knock down power coupled with decent accuracy for what they were doing.

    • B.B. Pelletier Says:

      flobert,

      I remember those cases. Weren’t they primed by Eley? They were very uniform.

      B.B.

      • flobert Says:

        I don’t know if they were primed by Eley, but the indentation in the case is meant to keep priming compound in a more uniform ring around the rim, and there’s a good amount of priming compound in there.

        I suppose I could take one and yank it apart and take photos. I finally have a camera that’s good for close-ups again.

  • Mark N Says:

    B.B.

    Correct me if I am wrong but I think it is important to note that pellets that leave the barrel at super sonic speeds slow down to sub sonic speeds at normal target ranges. If the pellet were to stay well above the speed of sound during its entire flight to the target, as bullets do, it would not get buffeted. This is how I explain this problem to people who don’t know much about airguns but I could be missing something.

    • twotalon Says:

      Mark…
      I figured the B.C. for Raptors a few days ago at two different velocities (at the muzzle).
      Using the B.C. that I got with a 1100 fps M.V. , I plugged numbers into chairgun for 1200 fps M.V..
      I have shot them this fast in my Talon .177 18″ barrel.

      Starting at 1200 fps, they drop to 1100 fps in 7 yds. , and to 1000 fps in 14 yds.. That’s not 14 yds MORE…it’s 14 yds total. Very fast velocity loss.

      What sells is the outrageous claims with the light pot metal pellets. The mega magnums usually do not meet these velocity claims. Might be hard finding one that will shoot a heavy lead pellet with a good B.C. fast enough to get over the sound barrier at all, much less by enough to keep it supersonic for any distance.

      twotalon

      • B.B. Pelletier Says:

        twotalon,

        You got it! That is why it matters not one whit that the pellet starts out so fast. Better to have it retain more of its subsonic velocity longer.

        B.B.

        • Victor Says:

          B.B.,
          That’s an interesting statement. Are you saying that there are pellets that when shot at some optimum velocity decelerate less (i.e., maintain their speed better)? Is this generally true for heavier pellets? What would that optimum initial velocity be? My guess is that it’s close to 900 fps. Is that about right?
          Victor

    • B.B. Pelletier Says:

      Mark N,

      That is why I make fun of those advertised velocities. We all know they really fast ones (above 1,500 f.p.s.) can’t be achieved with anything less than a detonation.

      B.B.

    • BenEnglish Says:

      Mark,

      You’re on to something when you say “If the pellet were to stay well above the speed of sound during its entire flight to the target, as bullets do, it would not get buffeted.”

      However, it’s all pretty meaningless when it comes to air guns. Here’s what I mean – That “buffeting in the transonic range” does all sorts of weird stuff, including increase the rate at which projectile velocity is lost. Wind drift, for example, is a function of the rate of velocity loss and it gets worse in the transonic range.

      What most people don’t realize is how wide that range is. Grab any decent ballistics calculator and check the wind drift for a particular bullet (range, wind speed, choice of bullet don’t matter; just keep them the same), plotting out the results for every 50 feet per second increase from, say, 800 to 2500 feet per second.

      Wind drift will dip to a low point between 850 and 900 feet per second. Then the buffeting starts to kick in. Wind drift actually gets worse and worse the faster you go until (I’m going from memory, here, so forgive me if I’m a bit off) about 1500 fps. Then the drift slowly gets better as the muzzle velocity increases.

      You have to get up to about 2300 feet per second to get wind drift numbers that are back down where they were at 875 feet per second. Everything in between is worse.

      What that means is that for a projectile to completely outrun the transonic buffeting that negatively impacts wind drift (and accuracy, too!), it has to stay above about 2300 feet per second all the way to the target.

      Totally off-topic for one paragraph – If you read on long-range rifle forums, you’ll often hear people comment on how things seem to go to hell at a ridiculous rate between 900 and 1000 yards, far worse than the whole muzzle-to-900 range. Sometime they talk about how things fall apart at 800. No matter what number is in their head, it’s a result of the bullet slowing into that serious transonic buffeting that starts at 2300. It’s very difficult for some long range shooters to get this into their heads. They are accustomed to bullets that stay, at most ranges, well above 2500 fps. At those high speeds, wind drift and time of flight appear to track perfectly; they do, because all that transonic buffeting has been left behind. To solve the problems with “wind drift going nutso-bad in the last 100 yards”, you have to beat it into their heads that drift doesn’t *actually* track time of flight; it tracks with the rate of velocity loss.

      No air gun that I know is launching any projectiles above 2300 fps.

      So while you’re on to something, I just wanted to point out that the definition of “well above the speed of sound”, a range where transonic buffeting becomes a non-issue, is way higher than most people realize and way higher than might be applicable to anything normally discussed in this venue.

      While there are plenty of good reasons to want higher velocities (e.g. better terminal performance when shooting something that breathes), my general rule is that for best accuracy and minimized wind drift, I keep muzzle velocities between 850 and 900 FPS.

      Ben in TX

      PS – Yes, I’m an air gun noob and most of the above was learned in long range rifle and pistol silhouette shooting, so anyone should feel free to flame me at will. However, the oddities of bullet flight in the transonic range is a subject that has fascinated me and that I’ve studied extensively for the last 3 decades or so, so I couldn’t resist posting an observation or two. Hope I didn’t offend anybody. I know how irritated people can get when some nonmember of the established community jumps in and starts pontificating so I figured I might as well apologize in advance. :-)

      • J-F Says:

        No one gets flamed here, if you’re wrong you’ll probably be corrected but never flamed.
        Welcome to the blog.

        J-F

      • Mark N Says:

        Ben,

        Wow what a terrific explanation. No worries about being a noob. I don’t often post but have been following this blog for years. I had no idea the transonic range was that wide for our purposes. I assumed that a pellet traveling a 100fps or so above the sound barrier would be out of harms way. Not so it seems. I was trying to point out on the blog that pellets don’t maintain these speeds for long because they are light and are high drag and thus slow down quickly through the transitional range when they leave the barrel at super sonic speeds. I now realize that even when they leave the barrel they are still in the zone where buffeting is greater.

        Your response is just the kind that keeps me interested in this blog. I can learn something almost every day from the knowledge and intelligence of other posters. Thanks again!

        Mark N

  • Iyonk Says:

    Hi BB and Edith… i have a question about the podcast…

    i’ve been waiting for new podcast since may, but so far there’re arent any new ones… hope the podcast wont be abandoned since i’m a BIG fan of the show…

    Thanks alot Tom and Edith..

    Iyonk.

    • Edith Gaylord Says:

      Iyonk,

      Last week, I reminded Tom about the podcast and that he needs to do one every month.

      Edith

      • Iyonk Says:

        Thanks alot for the kind reminder and info edith…. i’m looking forward for the future podcasts…

        have a great day to both of you…
        iyonk

  • J-F Says:

    I have an off topic question regarding the Bronco.
    I also hang around the Canadian Airgun Forum and have noticed a lot of new guys coming in recently and for most the 1000fps magnum springers are out of the question since they don’t have a firearm permit (which are a pain to get here) so we have to keep it around the 500fps mark which is just where the Bronco is, the law says that to be considered a firearm :
    “These are air guns with both a high muzzle velocity (greater than 152.4 meters or 500 feet per second) AND a high muzzle energy (greater than 5.7 joules or 4.2 foot-pounds)”
    if I’m not wrong the Bronco is very close to this, how hard would it be to bring it down a tiny little bit to met our regulation?
    Pretty much everything that’s affordable in that category is detuned Phantom and quest rifles from Crosman and the IZH-60/61 which a lot of people don’t seem to like very much.
    There’s always rifles like a slightly detuned HW30S and Diana 240 but we’re far from newbie pricing here.
    The Bronco is such a great rifle and a perfect first rifle.

    J-F

    • Volvo Says:

      The easiest way to slow a spring gun down is to smear a bunch of JM heavy tar on the spring.

      Or get one with less power to start:

      http://www.pyramydair.com/p/hammerli-490-express.shtml

      or buy one of the many de-tuned rifles I see on-line at Canadian dealers.

      It is hard to believe that in a Country with such wide open spaces they limit airgun power the way they do, makes the 12 ft lb limit in the UK seem blistering. Very sad.

      Do they actually check airguns for power? So many variables on a springer, if so pull the breach seal out.

      • J-F Says:

        It wouldn’t be for me! I already have a Bronco, illegally, but if you guys don’t tell I won’t either and since I’m not doing any criminal activities the chances of the police showing on my door step to take away an airgun that’s half a foot pound over the limit is quite small and the Bronco is well worth the risk!

        I just think that it would be an awesome rifle to have available here.

        Most of the detuned Crosman and Gamo’s available here have the horrible trigger that can be replaced by the GRT III.

        Don’t get me wrong we have awesome detuned rifles but not many are of this quality in that price range.

        J-F

        • Volvo Says:

          I guess I missed that part.
          So if you want to be legal for less, then go to the Air rifle Headquarters site and order heavy tar. Smear it through the cocking slot with a screw driver.It wont take too much, she will shoot smoother and a tad slower.

        • CowBoyStar Dad Says:

          J-F…just a caution.
          In my job I deal with the RCMP. They do check these forums on occasion. I wouldn’t mention to often that you have an illegal gun.

          • Edith Gaylord Says:

            CowboyStar Dad,

            Still waiting for IT to figure out why your avatar doesn’t show up.

            Edith

          • J-F Says:

            Like I said it’s barely illegal, I’m busting the limit by a mere 8 ounces according to the one BB tested several months ago and it’s the only gun over the limit I own, I haven’t fiddled with the Alecto valve to gain more power as so many people do or things like that on any of my airguns, I sure hope our good RCMP officers have more important things to work on than busting thru my door for a rifle that “could potentially” be illegal… For all we know I could have one that got a tea spoon more lube and it could be a bit slower… I haven’t chronied it.
            With the right pellet pretty much any rifle could be made illegal.

            J-F

            • CowBoyStar Dad Says:

              J-F, you’d think the Mounties would have better things to do…but sometimes for a ‘make work’ project they will have someone spend a shift just going through the more popular firearms (and this inlcudes airgun) blogs that are known to be of interest to Canadians.

              • J-F Says:

                Well you had me worried so I got the rifle, pellets and chrony out.

                I tried 4 pellets (Gamo’s match, H&N, Crosman premier and some RWS HyperMax), only the HyperMax went over the 500fps limit, at 582.7 average to be exact but at 5.2gr it gives me 3.9 foot-pounds so it’s under the 4.2 foot-pounds making it… L-E-G-A-L :D

                The closest to the limit were the gamos at 493.6 fps.

                So come on PA, ship away! We need this great rifle here.

                J-F

                • Wulfraed Says:

                  Uh… If I interpret the quote, it is NOT take the lowest…

                  Velocity over 500fps
                  OR
                  Energy over whatever

                  is illegal.

                  You found a combination that exceeded 500fps. The energy clause basically means you can’t use an airgun to lob 4 pounder cannon balls at 475 fps (heck, 50fps would probably be too much… Yep… 5ft-lbs, 28000gr => 8.9fps)

                  I think a rolling bowling ball probably exceeds those legal limits…

                  • J-F Says:

                    The law thankfully isn’t THAT dumb (altough it’s already pretty stupid), to be considered a firearm it has to be over 500 fps AND 4.2 foot pounds.

                    They probably made this when super light weight pellets started coming left and right as it was only 500fps before.

                    I once tried some old pellets that came with a Marksman 1010 pistol, it was a very small BB with a plastic skirt, I put one in my IZH-60 and it went 700 fps :shock: it also felt like I dry fired the rifle so I didn’t repeat it with another one.

                    J-F

    • B.B. Pelletier Says:

      J-F,

      Getting one Bronco rifle under the limit would be no problem at all.

      Getting the entire Bronco line to0 be compliant with Canadian law is a different story. They don’t regulate it by the gun. They regulate by the specs of the gun, which means there needs to be a dedicated Canadian model made. That requires a big demand, to justify the cost of the new model.

      B.B.

      • J-F Says:

        It’s VERY easy to get one in compliance with the Canadian law… I didn’t do anything to mine and it’s already under the limit! Barely but still under the limit.

        People here keep getting and pushing other to get the Crosman Phantom 500 (which is 120$), with the Quest 500 going for 145$ I think the Bronco would be a better option than those two (and a lot of other similarly priced rifles).
        I’m sorry I just don’t get the hype over this Crosman family of airguns, I find the front plastic sight Crosman has been using for year fugly, especially when compared to the very good looking Bronco muzzle brake, once the front sight as been removed (and safely put away in a small ziploc bag with the manual) and a nice scope screwed on it the Bronco is one of the nicest looking rifles out there IMHO.

        I’m trying not to bug people too much about it because it’s not available here but it’s one of my favorite rifles and every airgunner should have one. It’s so cheap (as in not expensive not cheaply made), good looking and accurate…

        J-F

    • vich Says:

      Don’t you love gun control. Calling an air gun a firearm is idiotic.

  • kevin Says:

    When I finished reading todays article it reminded me of many discussions in the past involving Herb and rocket scientist Jane. I’m already seeing comments from veterans dissecting details and it’s fascinating.

    I get the impression that the primary purpose of this article is to educate a potential air gun buyer about the possible/probable pitfalls of velocity in air guns.

    Maybe a potential airgun buyer will read this article and realize that using velocity figures printed on the box is not the ideal primary criteria for your purchase. I hope so. Unfortunately, I doubt it. I’ve witnessed too many buyers at big box stores comparing their limited choices and end up choosing the one that has the highest velocity number printed on the box in their price range. I’ve talked to many of my neighbors at my place in the mountains that bought air guns for plinking and/or pest elimination and made their air gun purchase using the same criteria. The word is out that I’m an air gun addict so when they have problems with their guns they come to me. Usually the problem is that the gun is no longer accurate. Loose screws, broken scopes, broken scope mounts and/or poorly adjusted triggers are common on these cheap springers. These opportunities allow me to delve deeper into their airgun experience and with rare exception the owners of these “no longer accurate airguns” only tried one pellet (from the tin they bought next to the airgun at the big box store) and never had heard about the artillery hold.

    Pyramyd Air does a better job than any other air gun retailer about trying to inform their potential buyers about air guns. I stumbled across a “new” article on PA’s site the other day titled, “Which air gun is right for me?” The article is actually a reprint from Airgun Illustrated copyright 2002. When you consider that one could write a book titled, “Which air gun is right for me?” this one page article does a good job. Links to the discontinued Webley Patriot and discontinued Gamo 1250 Hunter are odd. In my opinion, this article raises more questions in a potential air gun buyer that it answers which I think is a good thing.

    I think it would greatly benefit PA and this blog if at the bottom of all the articles on the PA site it would say something like, “If you have any questions about air guns please ask it on our daily BLOG. Any and all air gun questions are welcome every day.” BLOG would be a hyper link.

    kevin

    • B.B. Pelletier Says:

      Kevin,

      That is exactly why I wrote this report. So that in the future the PA sales team has a place to refer people to instead of the entire blog. They are tired of explaining the same things over and over, so I gave them an aid they can use.

      B.B.

  • Volvo Says:

    Kevin,

    I think it is a bit of a catch 22, those that go to Wally World for an air rifle are no doubt doing little research or they would not be there in the first place.

    Awhile back PA had asked me to answer e-mails they would forward on what airgun to purchase. Evidently, they already get many inquires from the “contact us” feature already and expressed some difficulty in being able to respond.

    I think the reality is less than a dozen canned responses would work fine -which could be put in the form of a new article. But then most need to learn for themselves anyway, seems they will go out and buy an RWS 52 even if they are told otherwise. : )

    • Edith Gaylord Says:

      Volvo,

      Pyramyd Air gets so many requests for assistance that we now have several people answering questions on our live chat :-)

      I don’t think a dozen canned responses would work. I don’t even think 50 canned responses would work. It’s too personal for most people. They want 1-to-1 help because any answer that’s provided would generate more questions…and the revelation that the customer doesn’t even know which questions to ask. That’s why we’ve hired people who will hold their hands and walk them through the process.

      Edith

    • kevin Says:

      Volvo,

      Canned responses are better than no response.

      I’m a fan of the blog since the mass of airgunners here respresent a wealth of information and the dialog beats canned responses. I also know that no matter how many newbies get directed here by whatever method and no matter what or how many questions they have they will be treated with respect and patience.

      Hope all is well with you.

      kevin

      • Volvo Says:

        Edith,

        Many moons ago before I owned a PCP and years before I bought one I had inquired to several dealers for input with my criteria and the reply from PA suggested a multi-pump Sheridan – plus took a few days to receive. I had even told them I had a budget of about a grand. Sounds like they have made great strides if they have live chat now along with folks that know the products.
        Little trivia – did you know that when I first started to post the staff at PA thought I was an alter ego of Tom’s?

        Kevin,

        At the end of the day “canned” can work okay. I use it with my buyers all the time, unique as people believe their situation to be that is rarely the case. Of course I feign interest, take notes, and never let them know that I have memorized a script for nearly ever occasion.

        As far as the Marauder, the sale had little to do with the rifle. Simply some unfortunate news that corresponded to the morning after its arrival. I will expand at some latter date.

        Best regards,
        Volvo

  • AlanL Says:

    Durn! That B.B. is always against everything I like: BIG recoil, 1700 fps and a satisfying splat 4″ wide of the target every time! ;D
    -AlanL

  • Matt61 Says:

    Quick fact: the slide on a 1911 moves at about mach 2 according to Stephen Hunter!

    Edith, I’m glad to see that our photo winner was not smoking a street light after all.

    Victor, I was in competitive rowing for awhile and a coxswain at an elite level said that the ones who succeed have the biggest egos. Why else would they put themselves through that misery? Maybe that’s why I didn’t last in that sport. :-) Would you say the same is true of elite shooters? :-) The principle would seem to apply to any competitive endeavor.

    AlanL, yes Zaitsev was real, but if his German antagonist was not real that would undercut the sniper duel although not Zaitsev’s other exploits. By the way, I believe that Zaitsev’s tally of ~250 was well below that of Lyudmila Pavlichenko. And here’s another couple of anecdotes to enlarge out understanding of the Eastern Front. A German veteran reports that he was ordered to escort a captured Russian commissar to a prison camp and certain death, but in the middle of the forest, he told the guy to start running. The Russian kept looking back expecting to be shot, and the German said, “Don’t be afraid. I’m not a murderer. I’m a human being.” (!)

    And for sheer guts on the Eastern Front you cannot beat this other anecdote (this was all on a YouTube documentary). After three days, a German soldier went to his ordnance officer, turned in his weapons and said that he wasn’t going to take part in “this war.” (!) Can you imagine the look on the face of the ordnance officer!? The soldier’s stated reason: “I was brought up to have respect for people.” And he did not end up participating in that war….

    Matt61

    • Victor Says:

      Matt61,

      I’m sure that ego plays a role in many cases in shooting, but I don’t think it’s the same as in rowing, as this one person described. Shooting is not a sport that puts one through “misery”. Shooting, for me at least, is about overcoming oneself, usually mentally. It’s much more subtle than that. For me, this is similar to how I never looked at my guns as weapons. I saw my guns more as instruments. Also, the best shooters that I personally knew were in fact extremely humble, and never bragged. Different from every other sport that I know, winners in shooting NEVER get in others faces, nor do they jump around, demonstrating how proud they are for winning. We were taught to maintain our respect for our fellow competitors, win or lose. True sportsmanship was our culture, and many parents found that to be a very attractive thing, after experience Little League (according to some). Oh, there were times when I really wanted to jump up and down, but I knew that it was wrong, based on how I was taught.

      Karate in our particular dojo was tortuous, but we didn’t tolerate it out of ego. We subjected ourselves to unimaginable pain because we knew that it mattered. The harder we worked, the less likely we were to get hurt, and the better our bodies performed. Incidentally, you grew up in Hawaii, so you were exposed to some very good dojo’s. We found that the most competitive dojo’s were from Japan and Hawaii.

      Anytime you want to be a winner, the ego plays a role, but it’s more important to do things out of love. The best that I personally knew truly loved what they did, and that made it much less painful. I shoot purely out of love for the sport, and it never matters that I beat anyone again. BTW, I’ve kept a small fraction of all the medals and trophies that I’ve ever won, and no one will ever see any of them if they walked into my house.

      Victor

  • pete zimmerman Says:

    Well, that was fun.

    A magnitude 6 earthquake just rolled through northern Virginia. Surprised hell out of me. And it went on for what felt like the best part of a minute, so not to be sneezed at. I expect some after shocks too.

    But we’re fine in my family.

    pete

    • Victor Says:

      Pete,
      Good to know that you’re family is fine. Injuries in the US are relatively rare, provided you don’t panic, or are extremely unlucky. Just apply common sense. If inside, stay away from windows (especially children) and objects that can fall off shelves or walls, and don’t turn on electrical appliances and switches until you know that gas lines are still intact (i.e., not leaking). I’m sure you know the drill.

      In any case, assume it ain’t over, so be extra careful for the rest of the week or so.
      Victor

      • pete zimmerman Says:

        I do know the drill. I experienced the San Fernando Valley quake in February, 1971 where many were killed. That was much bigger and was really frightening, coming as an ‘alarm clock’ at about 6:00 AM. This was a completely different experience. So far, no aftershocks big enough to feel. And USGS hasn’t reported any either.

  • Mach-1 Says:

    Hey all you Discovery and TKO LDC lovers. Check this out:
    http://www.network54.com/Forum/581291/thread/1314123731/Discovery

    It has been a long time since I posted anything here. But I read almost very blog and it is still great.

  • Wulfraed Says:

    How fast is the sound barrier?
    The answer is: it depends. Things that change the speed of sound are the elevation above sea level, the ambient temperature and humidity. Elevation is subtle, because it also influences the air temperature.

    To really put that into perspective… At operational altitude, the U2 has only something like a 40-60knot window. Too fast and the wings will be ripped off from the shockwave, too slow, and the wings will stall in the thin air.

    Imagine trying to drive a car whose engine will self-destruct at 5500RPM, but doesn’t have enough torque/power to prevent stalling when running below 4500RPM (granted, it will probably have the transmission from a long-haul tractor/trailer rig to get enough gears to permit some control of speed within that window)

  • Wulfraed Says:

    Oh, BTW… Seems to be a spammer hitting older threads… Signature seems to have variants of “electronic lock” and “security”

  • Frank B Says:

    Here’s something amazing and crazy from recent gov’t testing.They are working on an unmanned aircraft that flies in low orbit,put there in a piggy back ride with a booster rocket.It has not survived a full test after 2 tries……but the last one destructed over the Pacific(as designed,for safety) only after logging data for 139 seconds.Here’s the crazy part…..it was travvelling at between 17 and 22
    times the speed of sound!!!!!!!!!!!!!! Someone with more time and desire can calculate the exact numbers,but that is in excess of 13,000 MPH.

    • flobert Says:

      The way I understand it, those little robot planes are supposed to be able to cruise around at high altitude for long periods of time and then if needed, dive in (maybe jettisoning their wings?) at *very* high speed to strike a target, using sheer kinetic energy to destroy it.

      The Space Shuttle came in at an astounding speed too.

      • Frank B Says:

        Thanks,Flobert…..I left that part out.My typing finger gets tired! The reported velocities just blew my mind.I guess the “program” is the Cold War part Deux.That explains why so much money can be blown to smithereens.

        • flobert Says:

          The US is really a military with a country, rather than a country with a military. I think WWI was when our military got a taste of nearly endless money, and it’s just built up more since then.

          • Wulfraed Says:

            If it has so much, it isn’t trickling down to the contractors…

            {4.5 weeks to layoff}

            • flobert Says:

              Ouch, dude.

              Supposedly there’s a contract to build a bunch of circuit boards, perhaps program them, floating around out there with my name on it, but I’m not holding my breath. This economy is great for experiencing firsthand the graininess of Nature.

              Have you got your CV up to date and getting those applications spread around? Is Monster dot com any good these days?

              I had a motorcycle come in today, it’s pretty rough. I think if I have sense I’ll sell it and convert the $ into a gun – air or firearm to be decided.

              • Wulfraed Says:

                Been looking at resume guide books… And may have to pay someone to convert to a “functional/skills” format. I don’t think my two-page, one-employer, chronological is going to do it for anything except another defense contractor. (22 years of which is: I can’t go into more details that that}

                I also don’t intend to hang in the SF Bay area hoping to find a position before severance and unemployment run out; Michigan may be trash for jobs, but it’s also cheaper, and the rest of the family is there. My concept is to spend most of October working resume and boxing up the porcelain figures and books, rent a 26ft U-Haul (Hoping my stuff will fit — they rate it for a 4 bedroom capability, but they base that on maybe four beds, a desk, kitchen table, a few cabinets… I’ve already got 80 cubic feet of boxed books in storage [a stack 10 feet long, 2 feet wide, 4+ feet high] not to mention the 7 bookcases that don’t collapse). Drive to MI, unload (somewhere), fly back, clean apartment, drive Jeep to MI… With luck I’ll be there around Thanksgiving with everything (depends on the timing of a dental implant — if the surgeon okays it at the Oct 15 check-up, I should have the crown placed early November).

                • B.B. Pelletier Says:

                  Wulfraed,

                  What do you do?

                  B.B.

                  • Wulfraed Says:

                    Software engineer…

                    Last ~7 years on the SBIRS GEO program at Lockheed Sunnyvale. Problem: We launched the GEO-1 bird, so the program is no longer considered “development” but “maintenance”, so we are taking a major hit on manpower (besides the general downsizing any Google News search would bring up).

                    • B.B. Pelletier Says:

                      Wulfraed,

                      What languages do you know? Machine code?

                      B.B.

                    • Wulfraed Says:

                      {the nesting is out of reply levels}

                      Most recent usage: Ada with a smattering of Python. One assignment 7 years ago using Visual C++ 6 (ugh). Most of the prior program was VMS FORTRAN 77 (one small job with Fortran 90); had to glance at VMS Pascal once. I used to be able to do all sorts of things with F77 and VMS system calls. A major assignment in C 20 years ago (compounded by the, now unheard of, graphical kernel system on top of raw DECWindows [low-level X toolkit, not even a GUI design tool]).

                      No assembly languages since my college days (Xerox Sigma-6 Meta-Symbol, PDP-11 Macro-11). Not much OS interfacing since the VMS days (a small bit with the VC++ to access low-level parallel port).

                      {I was about to provide a link to an online PDF of my resume to simplify this, but the company firewall won’t allow FTP PUT operations}

                      Amiga variant of REXX in the late 80s/early 90s.

                • flobert Says:

                  You’re just doing what everyone is doing; moving to where you have some sort of tribe, whether it’s family or not.

                  I suggest the site Survivalblog for good reading for these times.

            • pete zimmerman Says:

              Less than one day…

    • Wulfraed Says:

      Why, when it’s been done <G>

      http://www.grc.nasa.gov/WWW/k-12/airplane/machu.html

      Between about 40k and 85k there appears to be a minimal change in speed-of-sound with altitude.

      • B.B. Pelletier Says:

        Wulfraed,

        “Not even a GUI interface…” It is to laugh! Back in my day the software engineers were designing their own semi-GUIs, because everything was in machine code.

        The FORTRAN will stand you in good stead in the business world, because those older mainframe programs all need maintenance and there are fewer and fewer people who understand the code any longer. Of course the maintenance tools are all home-grown, but after five years on the job, you ARE the manual.

        Might I suggest you inquire at the governmental level?

        Get copies of The Washington Post (at the library) and look at the classified ads. NSA, CIA and the rest of the Defense Department will be looking for older heads like yours to keep their ancient systems running. You’ll need a clearance, I am sure, but with your recent job your background check is probably still current and transferable.

        I was once a Defense Contractor who taught the FAR to government procurement personnel, and I know what I’m talking about.

        Prepare to relocate to the east coast, somewhere close to the DC Beltway.

        B.B.

        • Wulfraed Says:

          COBOL would be more likely for “business” applications — too bad the Fujitsu COBOL 4 that was included in a text book back around 1999 (guess Y <G>) won’t install on WinXP (and I no longer have a W9x system).

          Virginia is a “shall issue” state, is it not? Though my current Secret clearance expires in January… In a case of the left hand not knowing what the right hand is doing, three weeks after receiving the 60-day notice of lay-off I received an email giving me one week to fill-out and submit the paperwork for a renewed background check… It would be interesting to know if they complete it before I’m out the door, after I’m out the door, or just cancel it in mid-investigation. After 20+ years of being black, I don’t want to return to special programs…

          Managed to get my “current” (ie; still too long and too cryptic for outside industries) resume onto my website (discovering that a registry glitch I’d had earlier this year forcing me to recreate a new user account also lost my HomeSite defined deployment server definitions — at least I know my own passwords; but I lost the password for the Bestiaria site I do updates for)

          http://bieberd.home.netcom.com/DLB_Resume.pdf

          • B.B. Pelletier Says:

            Wulfraed,

            Secret is a bit too low for what I am talking about. You haven’t had a proper background check (a rectal exam) and a polygraph yet. That all takes time, but you have to start somewhere.

            Get the Post and start looking.

            B.B.

            • Wulfraed Says:

              I’d undergone the “small” polygraph test once, when I was still in special programs… My current Secret is the result of an administrative downgrade from TS/SCI; but is also obviously way out of date as TS needs 5 year updates and I’ve just submitted a 10 year…

  • Victor Says:

    B.B.,

    We know that there’s a huge market for MACHO air-rifles that shoot 1000+fps, but we also know that few actually achieve those velocities with “real world ammo”. Even if they advertise 1200 fps, we know that we’ll really get closer to 900 fps with decent ammo.

    Maybe this article can be the start of a better campaign, where instead of boasting unrealistic high-end velocities that push the sound barrier, air-gun manufacturers and retailers will boast more realistic (lower) velocities with high-end, super accurate, ammo.

    If we hunt or plink for fun, then we do want a gun that is harder hitting at, say, 50+ yards, but we want that gun to be accurate too. I’m happy with any ACCURATE air-rifle that can fire at 900 fps. I love the fact that I can reliably hit a 7″ metal plate at 100 yards with my Gamo Hunter Extreme, and my Crosman Titan, both in .22 caliber.

    Victor

  • JohnG10 Says:

    Anyone have any experience with hand pumps ? Are any of the pumps more reliable, or better working than the Benjamin pump ? Do they all have grease exposed when the pump handle is accidentally raised a bit during transport, etc ? If so, do any of them have a way to lock the handle down during transport ?

    Thanks,
    John

    • B.B. Pelletier Says:

      John,

      Yes, ALL hand pumps have grease exposed when the handle is raised. Don’t touch it or let it get dirty.

      The Hill pump has the reputation of being the most rigged on the market. I used an Axsor for 11 years and watched it die when a newbie bled the air on dusty ground one day. I didn’t think fast enough to stop him. A Hill would have been killed in the same way.

      B.B.

  • JohnG10 Says:

    Thanks. Do you think the Axsor is any better than the Benjamin pump ?
    Also, what happens when the air gets bled on dusty ground ? Does dirt get in the grease, and that grit grind the pump internals “if” it gets used before the dirty grease is replaced by new grease ?

    • B.B. Pelletier Says:

      John,

      The Axsor and Benjamin/AirForce pumps are roughly equivalent, with longevity going to the Axsor and maximum fill pressure to the Benjamin.

      Yes, all dust that gets into the grease ruins the seals in short order.

      B.B.

  • B.B. Pelletier Says:

    Victor,

    I saw that report. I am a skeptical as you about it, but as I am also too wimpy to shoot either cartridge, it’s a moot point.

    B.B.

    • flobert Says:

      I think with the .338 “la-poo-poo” there’s more choices in terms of bullets and it’s actually been used in some serious match shooting like the Wimbledon etc., and there are some loads that are indeed more accurate. I think with the .50 they’re just using standard military “ball” which is a FMJ “spitzer” bullet just like .30-06 scaled up. With the Lapua, for sniping, they can use target loads which I believe would be a Sierra match king bullet etc., a “pet load” for accuracy at 1000m+.

      Don’t look at me I’m not gonna shoot those things!

      • Wulfraed Says:

        If it’s military, they can’t (normally) use expanding (soft nose/hollow point) rounds… per the Hague Conventions

        http://avalon.law.yale.edu/19th_century/dec99-03.asp

        Though there appears to be some sort of escape clause in that “non-contracting power” (but, since the main targets tend to get their weapons from contracting powers, I doubt one could argue we could go “first use”)

        • flobert Says:

          Well, here’s the deal. As I understand it, Lake City Match .308 ammo had Sierra MatchKing bullets, which incidentally, have hollow points! Now the opening in the front is teeny, and they’re not really *intended* to expand, but to help concentrate the mass of the bullet near its center for accuracy. I believe this has been the state of things for decades now.

          As always, I write first and then I might research, so feel free to check up on this.

  • The Big Bore Addict Says:

    Wow… Look what I started. lol

    Talking about all these magnum airguns that don’t achieve their advertised velocities,
    I’m still waiting for someone to actually come out with one that does it with a lead pellet
    (maybe .22 cal 14.3 gr. or so) & see them name it;
    “The Mach 1 Airgun”
    LOL

    With what Kevin said about witnessing “too many buyers at big box stores comparing their limited choices and end up choosing the one that has the highest velocity number printed on the box in their price range” I’m betting the gun may be a hit not only because it actually does it, but even more so just because of it’s name! LOL AGAIN! :D

    HEY… I might be on to something here. he-he

    B.B. You might want to pass that on to Joshua so he can be the first & corner that market. ;)

    All joking aside, I actually like that name. You could call it;
    “The REAL – Mach 1 Airgun – ”

    What do ya think?

    TheBBA

    • B.B. Pelletier Says:

      BBA,

      The name Mach I was used 20 years ago by Ivan Hancock who broke the sound barrier with it.

      Sorry,

      B.B.

      • The Big Bore Addict Says:

        Well I suppose I can’t be too bummed out over that, because at least someone else thought is was a good name too. lol

        TheBBA

  • Charlie in Mo. Says:

    I have been a shooter and reloader since a teenager I’m 65 now an ol geezer. I recently purchased a ruger break barrel advertised at1000fps. Very dissapointed with accuracy. Thought about rifling ,twist in barrel.speed,shape of pellets. tried about 10 different 0nes to get 1 moa. at 20 yards. didn’t happen. Discovered after looking at wood targets that many of the pellets hit sideways, some polimer tips hit target 180 degtees.,hit the target backwards skirt first. Thanks for writing about this it makes sense to me. I somehow felt the speed of the pellet must have an adverse effect on accuracy. So I broke out my old Benjamin pump up and these pellets of light weight shot fine. Did find heaverier pellets shot better in the ruger but still terrible according to my expectations. Could babble forever I guess butenough. I agree stay under 1000 fps. or change rifling or desigh of pellets. thanks for listening.

  • Ron Says:

    What a great article. I had heard some of this information about staying subsonic with pellets before, but this article explained it really, really well. Thanks very much for taking the time to compile this.

    Ron

  • Dennis Brooks Says:

    The main reason pellets are not accurate in high velocity guns is that most are deformed into a pointed barrel before they leave the muzzle. You can achieve supersonic velocities, but the “bloom” of air behind the pellet as it leaves the muzzle makes quite a bang. The pellet itself produces only a snapping noise due to its small size. Longer pellets with solid cores deform less, retain more of their design shape and are therefore more accurate. It is not so much a function of speed as it is the loss of the designed aerodynamic shape. I have an extensive article with photos of recovered pellets from the 1200 to 1650 fps air rifles. You can achieve the speeds with light alloy pellets, but the due tend to tumble fairly quickly. Anything above 800-900 fps has enough pressure in the barrel behind the pellet to deform the skirt and waist. My RWS 48/52 is accurate to 100 yards with the right pellets. My GAMO Hunter Extremes are also accurate with the right pellet and hold.

  • Bob Says:

    The article helped me understand what happens to airplanes and projectiles at, or near the speed of sound.

    I was introduced to the sound of supersonic bullets, when taking my turn in the target pit at a high power rifle match, several years ago. The bullets sounded like fire crackers, as the passed objects.

    In my youth, shooting .22 rifle competitions, I quickly discovered that subsonic rounds shot tighter groups. I have no doubt that air gun pellets also have better accuracy in the subsonic range.

  • Carl Hall Says:

    OK, now I’m officially confused. You guys are the experts but I thought I had made supersonic work within my ‘guidelines’…real world testing and hunting. My example in this case is a BAM B-51 PCP in .177, modified with a tensioned barrel. Now I had heard about the sound barrier and yet wanted more power for shooting feral animals inside city limits. So using information I got on the Yellow forum/Chinese Air Rifles I tried helium which gives higher velocities.

    Yes, I found lighter pellets that had good accuracy became terrible groupers at higher velocities. But the rifle had always shot better with heavier pellets anyway and with Kodiac Heavys was a one hole (1/4″) rifle at 35 yards, tending to open up to 5/8″ at fifty. I wanted the best ‘kill’ power at fifty, my criteria being able to shoot through four antifreeze jugs full of water at 50 yards [that's 8 layers of that tough plastic and over 14" of water] which in my experience if a bullet will do that it will have sufficient lethality for a coyote or medium dog. I modified the rifle by opening up the port and adding in a throttle screw and changed the hammer spring and was shooting at 1050FPS. And yes, lost accuracy. But I thought that if I got the pellet ABOVE the speed of sound long enough that the pellet traveled 50 yards before dropping below the sound barrier and tumbling it would work. And that is what I think I have achieved. The pellets shot with He crony at 1220 and at first were tumbling before 50 yards. Thinking that this was because they slowed down too fast, I modified/streamlined the pellets by using ‘hot glue’ and a home made ‘sized die’ to fill in the wasp waist on the pellets to make a smooth sided cylindrical pellet (learning that the pellets have to be pre-heated and the die has to have PAM nonstick and all sorts of little tricks). In the process, the hollow base becomes filled to become a flat base. And these pellets DO group acceptably well up to 50 yards, then somewhere just beyond, tumble and open up groups (showing sideways on the target at 65 yards but I did not try to see exactly what range it happened). I still get 1/2″ average groups and sometimes LESS with this setup. My point is that it IS possible to get supersonic USEFULLY (increased power within a ‘normal’ range) with a with a little extra work.

    • B.B. Pelletier Says:

      Carl,

      You may be confused, but it’s at a higher level than this report was written for.

      You are confused because when the diabolo shape is changed, the flight patterns also change. You have done away with the high drag with your hot glue experiment.

      What you are designing has already been built at tested to 200 yards. It’s an AirForce rifle fired on helium with solid pellets. However, in that case it is no longer a pellet gun, but a replica firearm, because of the hyper velocity. The use of helium gives you the extra velocity, but it also brings on a batch of support problems — the first of which is obtaining helium and adapting the gun to use it.

      Hang in there. You are on a wild ride.

      • Carl Hall Says:

        Actually, getting the helium is easy. I buy it a WalMart in the Balloon Time 14.9 cu.ft size. or it is available at lots of ‘party supply’ stores or direct at http://www.balloontime.com/party-supplies/helium-balloons.aspx

        I then run a hose from the tank to my Hill pump. I just crack the valve on the He tank so I am getting a slight positive pressure to the inlet of the pump. And use the pump to fill the rifle. Note; it will leak down in two days since the He molecules are so small the O-rings are basically porous to the gas. Plus, it uses about 35% or 40% more gas per shot so there is a reductions in the number of shots in the PCP tank. It drops me from 40 ‘sweet spot’ shots to 25 ‘full power’ shots +-, But since I only load with Helium to hunt varmints in the Houston city neighborhoods, it works quite well.

  • Big Al Says:

    What about the issue of heavy pellets being bad for spring gun springs and seals?

    • B.B. Pelletier Says:

      Big Al,

      Good question. I don’t believe all that’s been said about heavy pellets being bad, but I also admit I don’t know for sure.

      B.B.

    • Wulfraed Says:

      (Hypothetically) I can’t see how the pellet weight could affect the spring itself — at most the back-pressure is slowing the spring action at the end of the stroke and buffering the piston shock. Piston seal? Maybe if the same back-pressure is strong enough to cause blow-by of the piston.

      A super-light/under-sized pellet could potentially be worse — since it will develop lower peak pressure. The reductio ad absurdum argument is: no pellet… No back-pressure piston/seal slams into the end of the cylinder at full speed, spring probably goes into oscillations (the middle of the spring has been moving forward at half the rate of the front part — now the front comes to a sudden absolute stop… middle will overshoot, bounce back, repeat until dampened out). On the other side — weld the bore closed about half an inch in… the only escape for the pressure build up will be to leak past the piston seal, and whatever seal surrounds the loading port. Unless such leakage physically rips the seals all I see is perhaps increased wear (piston seal, especially if it expands against the cylinder bore). Spring should be fine since it comes to a nice slow stop.

      Heavy pellets should produce a higher peak pressure, and less overall acceleration of the pellet; when the effective muzzle energy becomes less as the mass is increased, one has probably reached the desirable limit on pellet weight — there has been too much velocity reduction to maintain equivalent energy. My NRA 1000 (Gamo Shadow) .177 seems to be a fairly firm 13ft-lb class using pellets from 6.9 to 8.3gr (12.4-14.0ft-lb, though not in that correlation). Hit a 9.2gr pellet and above, and it struggles to do 10.5ft-lb. My RWS Mod54 .22 is nicely 19+ft-lbs with 14.0 to 18.2gr pellets (18.1-20.4ft-lbs) but drops to <15ft-lb when the pellets are in the 20+gr range.

  • James W. Adams Says:

    I disagree with this hypothesis. Have you ever fired a .220 Swift firearm? That rifle has one of the highest muzzle velocities of any firearm, yet is quite accurate if well made and fired with quality boat tail bullets.

    The F-14 Tomcat can easily exceed Mach two in stable level flight. One of the key features to designing such an aircraft is elevating the rear control surfaces out of the shock wave from the front surfaces. That was the key problem with WW-II era aircraft. Indeed, the F-14 is one of the fastest aircraft ever made short of the SR-71 Blackbird.

    A key purpose of the skirt of the pellet is not to stabilize it in flight, it’s to form it to the rifling so it has enough spin to stabilize it. Perhaps the problems you saw are from having a pellet that is too nose heavy. In that case aerodynamic forces are going to cause it to want to swap ends like a badly designed sports car. And there aren’t many supersonic sports cars.

    • B.B. Pelletier Says:

      James,

      Your argument proves my point. You mention the .220 Swift uses boattail bullets. Of course it does. Those bullets were designed for supersonic flight.

      The diabolo pellet was not designed for supersonic flight and will destabilize when it gets up into the transonic region. So, because an airgun can just barely break the sound barrier and because the diabolo’s high drag puts the brakes on the instant it hits the air stream, you have the incredibly bad situation of the lightweight pellet being tossed around by buffeting from the moment it leaves the muzzle until it has decelerated below transonic speed, which is the initial and most critical part of its flight to the target. Nothing could be worse, in terms of accuracy.

      Aside from the fact that this is exactly what aerodynamic theory predicts will happent, there is the overwhelming evidence that pellets that go this fast are simply not as accurate as when they remain below the transonic speed for their entire flight.

      B.B.

  • Chris Says:

    I’m a longtime rifle competitor…highpower, long range and smallbore. Some 10M air, mostly for cross-training. I’m a longtime recreational airgun shooter, but new to this new high velocity air stuff. I thought I’d comment and correct on some of the stuff I know about.
    a) Federal 22lr ammo – the dimpled base was used in their highest grade ammo. The dimpled base was actually used by the Russians much earlier in their Olymp ammo. The Federal ammo was supposed to be subsonic, but some found it went supersonic, so they produced an “A” lot and a “B” lot. It was used to win Olympic Gold (Meili) and Silver (Foth).
    b) The 338 Lapua “might” have been used at Perry for the LR Championships, but I doubt it, since brakes are not allowed. It was definitely not used to win Wimbledon.
    c) The 900 to 1000 yard line is not some magical distance where bullets go transonic and lose accuracy. This applies to a specific situation; The 168 Sierra out of a 308 Winchester goes transonic at about that range and loses stability. However it’s related to bullet design. Bob McCoy spent some time describing the reasons why in his book Modern Exterior Ballistics if you’re so inclined. The old military 173 M1 projectile does not have that problem. The more current 175 Sierra was based on the 173M1 and makes it to 1000 at 308 velocities just fine (that was one of the design parameters. Improving the BC of course is one approach. Improving the velocity would be another (ie. using a 300WM will keep the 168 supersonic and stable at 1K). Doing both with less recoil is where it’s at for prone shooters these days with the 6.5-284, and 6mmXC.
    d) The 220 Swift is a case study in many things such as improved barrel steel, bullet integrity, but the boat tail wasn’t an essential to making it work. A well constructed flat base shoots just as well if not better at shorter ranges (inside 300yards).

  • 17pr Says:

    Too many of the major brands have above 900 fps. No good low cost back-stops and moving targets available and too much bullet drift with wind.

    The air resistance is highest at the speed of sound and people wrote that it was impossible to break the speed of sound — that why they erroneously call it the sound barrier. The pellet or bullet loses speed the most around that region and will cause lots of drift with the wind.

  • Chris Says:

    Thanks for the welcome.

    It’s funny how reading through the posts, I see more than a few parallels between my powder gun experience and what ya’ll are experiencing with high velocity airguns. Pellet skirt distortion from high pressures = bullet “slump” from excessive pressures.

    So here’s where I get to ask about things I don’t know so much about…

    Reading through the comments, it sounds like the current pellet designs ie diablo are not cutting it for high velocity airguns. Has any of these manufacturers made recommendations on appropriate pellets for their guns? I would think that they would have the most to gain by the use of appropriate projectiles.
    Question for Dennis Brooks: Aside from light weight, what did the successful pellets look like?

    My powder gun experience tells me, using the wrong bullets for the application leads to miserable failures. One example that comes to mind is the standard 55gr 223 bullets being used beyond 300yds. It took going to heavy weight VLD designs to make the M16 competitive to 600yds and beyond. Might these high velocity airguns benefit from a similar redesign of the projectile? I remember when Crosman made first made their Premier with a less hollow skirt to limit distortion from the then state of the art high pressure guns.

    And a final question; Target 22LR ammo leaves the muzzle just shy of mach1 and can be exquisitely accurate (<.5 moa at 50yds and < 3/4moa at 100yds). Is there anything to be learned from 22LR projectile design that can be applied to high velocity air rifle pellets?

    • twotalon Says:

      You would not expect any manufacturer to suggest any particular pellet for best performance. They would have to drop their “speed sells” approach to marketing.
      Maybe “manufacturer” is not the right word. Too many name brands that are not really manufacturers of the guns they sell.
      Of course if they suggest any particular kind of pellet, they would suggest something with their name brand on it. What about when a pellet that SHOULD shoot well does not? About all anyone could say is “find a round nose or domed pellet in a general weight range for a general power range (for this model) that the gun likes. Then you run into exceptions.
      So we are back to where we started. You usually have to figure it out for yourself.

      Bullet design for airguns? For smaller bore airguns, bullets don’t work. Not enough pressure for bullet upset. Hard loading. Low velocities. Wrong twist rate.
      So what is to be learned about bullet desigh of match LR ammo? Same bullet shape as the high speed stuff, but look at he velocity range. It’s not the bullet….it’s the speed.

      twotalon

    • B.B. Pelletier Says:

      Chris,

      Monday’s blog addresses your questions.

      B.B.

  • Kyle Says:

    This is a strange theory, as most firearms break the sound barrier, and accuracy in maintained. Why would an airgun be any different?! Unless the pellets shape has something to do with it, in that case I would blame pellet design.

    • B.B. Pelletier Says:

      Kyle,

      To give a complete answer to your comment would take a book!

      First of all, nothing I wrote about today was theoretical. Everything was based on fact.

      Yes, most modern firearm RIFLES do shoot supersonic, and they do so at many TIMES the speed of sound. And they use projectiles designed to have high sectional density and low drag, so they don’t slow back down as fast as diabolos. So, yes, they do remain accurate for as far as they are still supersonic. But the moment they slow back down below the sound barrier, they also destabilize and become inaccurate.

      And as for firearms having problems with the sound barrier, that was well-known in the 19th century, as the destabilizing effect was noted on conical lead bullets. Back then, when the top velocities were on the order of 1,600 f.p.s. because of black powder, people had to load their rifles for stability at 100 yards or 200 yards or just load to the max and trust that they would be accurate enough to do the job.

      The buffalo hunters did shoot well out to 500 yards and beyond, but that was because their bullets weighed so much. A 500-grain slug doesn’t move around as much as a 55-grain slug when hit by the transonic buffeting.

      B.B.

      • Kyle Says:

        Than I am correct to assume that the flaw lies in pellet design, and not the velocity. Correct me if I am wrong. I really don’t think an individual needs to read a “book” in order to comprehend this.

    • Wulfraed Says:

      Most firearms stay ABOVE the speed of sound within their usable shooting distance.

      Airguns that break Mach 1 aren’t fast enough to keep the pellet above that speed until it reaches the target.

      Remember — the projectile doesn’t “break the barrier” after leaving the muzzle; it goes supersonic while still stabilized by the barrel, and as long as it stays supersonic it is “outrunning” its own wake. Let it slow down, and its wake comes up and slaps it in the tail.

      Come up with an air gun that can launch a medium weight pellet (without deforming it) at 2500fps, and it may still have supersonic velocity at 25-35 yards, and be accurate. What we have now are rifles advertised to launch at 1200-1400fps, but the pellets drop to subsonic before going 10 yards and get slapped all over…

      • Herb Says:

        Wulfraed,

        You are not wrong about the wake, but you miss one point. Air is compressible. So as the pellet is accelerated above the speed of sound in the barrel, it compresses a plug of air in front pellet which is expelled from the muzzle before the pellet exits the barrel. The muzzle blast immediately slows, but the pellet traveling faster than sound passes through this turbulence.

        Herb

  • Chris Says:

    Wulfraed,
    I used the example of 22LR match ammo specifically because they run just shy of supersonic at the muzzle. If the transonic zone is considered to extend down to mach 0.8, the 22LR spends a good amount of time transonic. In spite of it’s velocity in the transonic zone, the 22lr bullets are somehow able to remain stable and accurate, hence my question about taking design cues from 22lr bullet design.

    • B.B. Pelletier Says:

      Chris,

      I wonder that, as well. Of course the long rifle round has a 40-grain conical that isn’t as affected by buffeting as a diabolo, but still, I would think ammo makers would get it down, away from the transonic.

      B.B.

  • John Majkowski Says:

    Just got done reading your article, and found it rather interesting. The only thing I’m finding myself at odds with, is that I own a break barrel pellet rifle. It’s a Crosman Fury, using 4×32 scope a zeroed in at about 14 yards, though I have made longer shots.

    There are three types of ammo I used with it, now only one. Lead was the first, then I decided to test two ammo types, Crosman’s special alloy rounds which fired at 1,375 FPS Muzzle Velocity and Gamo’s gold PBA rounds at 1,250 FPS MV. It was even said on the package that it had a 90% weight retention.
    Crosman’s lighter weight alloy rounds never landed in the same spot twice with the same sight picture.
    However, the heavier Gamo gold PBA rounds almost landed atop of each other with the same sight picture, and now I swear by those rounds in particular.

    Could the weight retention have something to do with the PBA rounds being able to maintain the speed and accuracy I’ve noted with them?

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