I remember reading about something like this years ago. did anyone ever make it?

I remember reading about something like this years ago. did anyone ever make it?

250 Piece Survival Gear First Aid Kit

LifeStraw Water Filter for Hiking and Preparedness

250 Piece Survival Gear First Aid Kit

  1. 1 month ago
    Anonymous

    yeah

  2. 1 month ago
    Anonymous

    I'm interested. What's the advantage here/what's trying to be achieved?
    (People who actually know what they're talking about only, pls.)

    • 1 month ago
      Anonymous

      light weight/high stiffness

    • 1 month ago
      Anonymous

      >What's the advantage here/what's trying to be achieved?
      Supposedly, rifle accuracy can be determined by barrel stiffness because a stiffer barrel moves less during firing. However, just making it fat makes it heavy, so you want to utilise the fact that stifness increases by the third power of the distance that a section material is from the centerline of bending. Put simply: a 2 inch diameter tube with a thin wall can significatnly stiffer than a 1 inch diameter round bar. In OP's case, you have the inner barrel (liner) to provide guidance for the bullet and the exterior tube to provide stiffness.

      why would inducing a longitudinal stress be beneficial?

      Because Poisson's ratio is a thing. Once the cartridge is ignited, the chamber expands ever so slightly, meaning the barrel shrinks lengthwise. Then, this movement (both axially and longitudinally) creates vibrations along the barrel: of course in the axial direction (which should not affect accuracy), but also in the tangential directions, which can be split in horizontal and vertical movement. Provided a circularly symmetric barrel, these two movement components should have roughly the same amplitude and frequency. If you were to increase the frequency, amplitude goes down, meaning the muzzle end moves less and your bullets should exit said muzzle more consistently. The frequency is increased by tightening the oscillating member (giggidy), pretty much like tightening a guitar string. Note that this is for any given stiffness: if you increase the stiffness by increasing the polar moment of inertia of the bending member (giggidy), you also decrease amplitude.

      can you?
      How about you show me the math?

      Look up polar moment of inertia for the beam stiffness and basic string harmonics for the tightening bit.

      This is actually how all Dan Wesson revolver barrels are.
      The gap is only a couple thousandths of an inch, but the barrel and barrel shroud ARE separate.
      I think it was more for the ability to switch barrels on a whim, but they definitely are very accurate revolvers so maybe that tensioning actually does help.

      Honestly, with revolvers barrel stiffness is much less important than concentricity between cylinder and barrel - and of course the shooter.

      • 1 month ago
        Anonymous

        I am an idiot, third power should be fourth power. I was thinking in rectangles (1/12*bh^3) instead of tubes, which is what you get when you're used to beam calculations. My bad.

        You can't see the forest because of the trees.
        No shit tensioning a barrel makes it stiffer.
        So does making the barrel thicker. Which does the job better? Now you have to do the math with actual numbers.

        >muh second moment of area
        why are you ignoring the harmonics of the inner barrel? there's more going on here than just a bending beam problem.

        >So does making the barrel thicker. Which does the job better?
        As the stiffness of a tube increases by the fourth power of it's radius, it seems obvious that a hollow tube can be stiffer for the same weight than a solid tube. Of course any barrel is a hollow tube, but you get the idea. If you want the maths: a 60mm tube with a 50mm inner radius is stiffer than a 50mm solid round bar, while having less than half the surface area (and thus half the weight). Increase outer diameter while reducing wall thickness, and it skews even further (up to a point).

        >why are you ignoring the harmonics of the inner barrel?
        Not that guy, but the inner barrel's stiffness can be ignored as far as stiffness goes. That means you could consider it as a seperate beam that is fixed by the outer beam. Of course, the outer beam is now so stiff that it has relatively little movement in the absolute sense, thus, deviation is limited. However, the inner beam could still bend - but with relatively little torque reaction to do so, it would only move a fraction of a degree, not enough difference to make a difference. Again, not that guy, no need to get mad - this is pretty interesting engineering after all and warrants solid discussion.

        my niggy, I'm proud of you for even knowing what the second moment is, but you fail to address that making the barrel thicker also does the same thing. it does so while also making a smaller barrel assembly, a larger thermal mass, fewer parts, and without a tensioning system that would require a torque wrench to be repeatable.

        >smaller barrel assembly
        True, but the individual components are easier to manufacture. Hell, I want to try this with a sewer pipe one day to see if that would work, you tell me that wouldn't be easy.
        >a larger thermal mass
        Which can be compensated for by adding some aluminium, like the structured barrel concept.
        >fewer parts
        Fair.
        >and without a tensioning system that would require a torque wrench to be repeatable.
        You would not necessarily need a torque wrench for repeatability with one individual rifle, unless you are regularly removing the barrel.

      • 1 month ago
        Anonymous

        Thanks!

  3. 1 month ago
    Anonymous

    This is how Volquartsen does their carbon fiber 22LR barrel. I'm not sure it would work with actual rifle rounds.

    • 1 month ago
      caius

      BSF does their whole carbon fiber lineup with an air gap.
      https://www.bsfbarrels.com/shop-all

      I'm interested. What's the advantage here/what's trying to be achieved?
      (People who actually know what they're talking about only, pls.)

      Some /prg/ barrels are carbon wrapped for weight reduction. But the carbon fiber can act as an insulator. An air gap sidesteps this.

      • 1 month ago
        Anonymous

        >carbon fiber is an insulator
        They should sleeve it in aluminum then and make it a heat sink. Carbon fiber barrels are a meme anyway.

      • 1 month ago
        Anonymous

        Carbon fiber conducts heat along the length of the fibers. You can design a carbon fiber barrel to transfer the heat along the length of the barrel and heat it evenly, compared to a normal (all) steel barrel that disproportionately heats the throat and chamber.

  4. 1 month ago
    Anonymous

    why would inducing a longitudinal stress be beneficial?

    • 1 month ago
      Anonymous

      stiffness

      • 1 month ago
        Anonymous

        why not just use a slightly thicker barrel?

        • 1 month ago
          Anonymous

          because you can make it lighter and stiffer by tensioning it.

          • 1 month ago
            Anonymous

            can you?
            How about you show me the math?

            • 1 month ago
              Anonymous

              NTA, but you are an ass. The world does not exist to serve your demands. Another anon was nice enough to answer your repeated questions. If you want more information, stop being a helpless moron and Google it.

              • 1 month ago
                Anonymous

                >could you prove that's true?
                >NO, WTF IS WRONG WITH YOU YOU STUPID PIECE OF SHIT
                why do people get so mad when you ask them to do simple math? if you make a claim
                >this makes the barrel lighter and more stiff
                the logical response is
                >how much stiffer and how much lighter
                If you are incapable of rational discourse, or cannot actually determine if what you are saying is true, you shouldn't say it.

                BSF does their whole carbon fiber lineup with an air gap.
                https://www.bsfbarrels.com/shop-all

                [...]
                Some /prg/ barrels are carbon wrapped for weight reduction. But the carbon fiber can act as an insulator. An air gap sidesteps this.

                >But the carbon fiber can act as an insulator. An air gap sidesteps this.
                how is an air gap not an insulator?

              • 1 month ago
                Anonymous

                It's basic mechanics, you fricktard. There's nothing to prove.
                https://en.wikipedia.org/wiki/List_of_second_moments_of_area

              • 1 month ago
                Anonymous

                You can't see the forest because of the trees.
                No shit tensioning a barrel makes it stiffer.
                So does making the barrel thicker. Which does the job better? Now you have to do the math with actual numbers.

                >muh second moment of area
                why are you ignoring the harmonics of the inner barrel? there's more going on here than just a bending beam problem.

              • 1 month ago
                Anonymous

                my niggy, I'm proud of you for even knowing what the second moment is, but you fail to address that making the barrel thicker also does the same thing. it does so while also making a smaller barrel assembly, a larger thermal mass, fewer parts, and without a tensioning system that would require a torque wrench to be repeatable.

              • 1 month ago
                Anonymous

                >lighter and stiffer
                >but thermals, part count, etc.
                Come on.
                >a tensioning system that would require a torque wrench
                Like any other threaded rifle barrel?

              • 1 month ago
                Anonymous

                I have no reason to believe it's stiffer or lighter, let alone both. nobody can even provide dimensions of such a system so I can do the math myself, since all the turd-brain morons aren't capable of doing it themselves.

              • 1 month ago
                Anonymous

                Kind of beside the point really; the people who want a really stiff barrel don't give a shit about weight, the people who want a lightweight barrel don't particularly care about stiffness, and literally nobody wants a fragile barrel that's extremely heat sensitive.

              • 1 month ago
                Anonymous

                >everyone agrees with me

              • 1 month ago
                Anonymous

                The fact that nobody can point to a commercial (or indeed experimental) product is a pretty solid case in itself that nobody has a use for this even if it did work (until the barrel expands and throws everything out of whack anyway).

              • 1 month ago
                Anonymous

                Volquartsen makes tensioned rimfire barrels. BSF makes tensioned centerfire barrels. Possibly others but those are the ones I'm familiar with.

              • 1 month ago
                Anonymous

                >Volquartsen makes tensioned rimfire barrels. BSF makes tensioned centerfire barrels
                Yes but that's bullshit, the minimal tension there is entirely to stop the carbon fibre asploding when the barrel expands.

              • 1 month ago
                Anonymous

                CF wrapped barrels don't explode without tension or an air gap lmao. I swear to God threads like these bring out the stupidest fricking noguns morons.

              • 1 month ago
                Anonymous

                No, they delaminate which is a lot less entertaining. Most people want a higher rate of fire than a fricking musket before their gun becomes an hero.

              • 1 month ago
                Anonymous

                The rigidity in bending is proportional to the moment of area of the cross section. So ignoring any other considerations, for the same mass of material, increasing the diameter and decreasing the wall thickness gives more rigidity.

                Reference: https://www.physicsforums.com/threads/rigidity-of-tubing-vs-solid-bar.173192/

              • 1 month ago
                Anonymous

                duh, moron. but an infinitesimally thin wall is moronic, it still has to be durable enough as a free-standing structure to exist under use. that's why I'm asking for dimensions, because arbitrarily saying
                >it's lighter and stiffer
                when in reality it is also bigger, thermally sensitive, more complicated to produce, more complicated to use and requires a larger receiver, where hypothetical weight savings are lost.

              • 1 month ago
                Anonymous

                >thermally sensitive
                In what way? It's no more "thermally sensitive" than any other gun barrel.
                >more complicated to use
                How? Having to tighten one or two more things when installing?
                >requires larger receiver
                No, it doesn't really need to.

              • 1 month ago
                Anonymous

                >In what way?
                because the barrel liner will heat up more than the barrel support/sleeve.
                as it elongates due to heat, the tension will lessen, changing it's harmonics.
                >No, it doesn't really need to.
                yes, it absolutely has to, because the same feature that retains the barrel will now have to also transfer load from the barrel support structure back to the barrel. the only way it works is if that interface is bigger, because that's the entire theory of operation.

              • 1 month ago
                Anonymous

                even when all the tension is gone you still have a support at the muzzle which is more rigid than a typical barrel.

                as seen in the illustration, the sleeve can just shoulder on the receiver. every bolt action already has a receiver with a much larger diameter than a typical barrel.

              • 1 month ago
                Anonymous

                if it gets so hot to achieve zero tensions it's just as likely that it'll become compressive forces, at which point you are exerting a buckling load onto your barrel. How is that desirable? compared to a free-floated barrel. again, nobody has bothered to actually put down numbers, which means this is all hypothetical, where advocates get to hand wave away all problems because you don't have to stand and defend a design. it doesn't seem better than just having a monolithic barrel, for temperature sensitivity, thermal mass, ease of mounting and other reasons.

              • 1 month ago
                Anonymous

                >if it gets so hot to achieve zero tensions it's just as likely that it'll become compressive forces, at which point you are exerting a buckling load onto your barrel. How is that desirable?
                it's not. but that's also just your hypothetical scenario.

              • 1 month ago
                Anonymous

                You sound like the gay in the wrong place.

              • 1 month ago
                Anonymous

                could you try that again, but pretend you grew up in a real country and learned English as your first language?

              • 1 month ago
                caius

                >how is an air gap not an insulator?

                I should clarify - there's a lot of fuddlore and broscience around carbon fiber barrels. I'm not sold on even 1/4 of the common claims you'll see on gun forums.

                My point was just (1) to list one manufacturer with a full range of "sleeved" – cf. "wrapped" – barrels and (2) to provide the most salient argument you'll come across which is at least directionally correct.

              • 1 month ago
                Anonymous

                Here is my argument: tensioned barrels don't win any of the top tier rifle competitions and neither to carbon wrapped ones. Even the ones where weight is a factor either in determining which class a rifle falls into or because the comp is a timed event on a course the shooter has to run.

                The people who shoot these things are bad autistics and the difference between winning and losing is sometimes a fraction of a millimeter or a few seconds. If either tech could give them an advantage everyone would be using them.

              • 1 month ago
                Anonymous

                >to provide the most salient argument you'll come across which is at least directionally correct.
                no it's just flat out obviously wrong, there's nothing salient or "directionally correct" about it, you're just spreading obvious bullshit fuddlore. it's like trying to claim water gets denser when it freezes. you don't have to be a rocket scientist to know that air is gonna be a better insulator than a solid material like carbon fiber. I hate accusing people of being redditors but you must be a reddit transplant the way you just regurgitate bullshit you didn't bother looking into and the way you put a newline between every single sentence, and you really need to go the frick back there.

              • 1 month ago
                caius

                Trapping heat in a solid is not preferable to heating a gas that you are venting in turn. You are too blinded by your misplaced desire to be condescending. You have not yet found the discussion topic at hand.

                Here is my argument: tensioned barrels don't win any of the top tier rifle competitions and neither to carbon wrapped ones. Even the ones where weight is a factor either in determining which class a rifle falls into or because the comp is a timed event on a course the shooter has to run.

                The people who shoot these things are bad autistics and the difference between winning and losing is sometimes a fraction of a millimeter or a few seconds. If either tech could give them an advantage everyone would be using them.

                It's arguably worse than audiophile type consoomer stupidity because there's no magic phenomenological element to the empirical side of shooting. If blee bloo harmonics or thermal dissipation are really improved to the degree that manufacturers claim, we shouldn't see such mixed results as e.g. https://snipershide.com/precision-rifle/3311-2

                My impression is that people engage in illiterate flamewars about this topic largely because they underestimate the variability of CF's effects in different weaves, different configurations / orientations relative to heat sources, etc. It's just industrial inexperience.

              • 1 month ago
                Anonymous

                >there's a lot of fuddlore and broscience around carbon fiber barrels
                And a lot of moronic hype. A $4000 carbon fiber "mountain" hunting rifle somehow weighs almost exactly the same as stainless Ruger Scout. Granted the fudd gun has a 22-24" barrel. But an 18" barrel is fine. Even out west you're not shooting deer past 350 yards.

                I think a lot of hunters have a deep need to pretend they're doing something a lot more demanding than it actually is.
                >muh $800 coat
                Absolute morons. Just get an ECWCS shell from Goodwill.

              • 1 month ago
                Anonymous

                Back to r*ddit with ye

  5. 1 month ago
    Anonymous

    The center barrel does not have to be tensioned. To keep it straight and aligned with the much stiffer outer barrel, it would be enough to add supports every 10cm or so. These could look like washers, fixed at the outside, but with a minimum of play at the inside to allow for lenghtwise thermal expansion. This design would do a much better job at keeping the inner barrel straight.

    • 1 month ago
      Anonymous

      You're not trying to keep anything "aligned" or "straight", you're trying to keep the barrel tensioned.

  6. 1 month ago
    Anonymous

    This is actually how all Dan Wesson revolver barrels are.
    The gap is only a couple thousandths of an inch, but the barrel and barrel shroud ARE separate.
    I think it was more for the ability to switch barrels on a whim, but they definitely are very accurate revolvers so maybe that tensioning actually does help.

    • 1 month ago
      Anonymous

      >revolver
      Think about what you just typed.

      • 1 month ago
        Anonymous

        Thought about it. Don't understand how I'm wrong?

        • 1 month ago
          Anonymous

          You see that 3" barrel you just posted? Is it accurate? Is it measurably less mechanically accurate than the 7" one?

          • 1 month ago
            Anonymous

            Reread my post you absolute mong.
            Particularly the last sentence.

            • 1 month ago
              Anonymous

              The one that has
              >maybe that tensioning actually does help
              in it? The part that's ridiculous if you think about it for one second?

              • 1 month ago
                Anonymous

                >I think it was more for the ability to switch barrels on a whim
                You're blind and moronic and no guns.

              • 1 month ago
                Anonymous

                Making an obvious and true statement doesn't excuse the stupid one following it. Observe.
                >you are a dumb Black person but maybe you're so dumb you can actually fly
                See?

          • 1 month ago
            Anonymous

            They're both under tension when installed on the gun. I don't know what moronic noguns argument you're trying to make here.

          • 1 month ago
            Anonymous

            >w-well it's probably not enough difference to notice so it doesn't count!
            lol
            lmao

    • 1 month ago
      Anonymous

      >they definitely are very accurate revolvers so maybe that tensioning actually does help.
      I think the very small cylinder gap has more to do with that than the barrel tensioning. Old trick by silhouette shooters used to be to disregard the factory 6 thou gap recommendation and go for 2 thou, which is more in line with Freedom Arms (and will get you jammed if you get fouling). Could be fuddlore, but if you hit fullsize rams at the proper distance, you can shoot. On that note: frick turkeys.

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