If you try to achieve great velocity.

If you try to achieve great velocity. To do that, you need to have great acceleration, otherwise the barrel would need to get too long. Great acceleration means great pressure, which means the friction between the bullet and the rifling is also great, wearing it down quicker.
But the pressure is only that high at the start of the bullet's travel because the powder does not start burning faster while the bullet does accelerate. What if, to fix this, we added layers of solid propellant to start burning faster with time, like in picrel for example? That way the pressure can be about the same as the chamber pressure all along, and lower the chamber pressure required for the same velocity, making it possible for the barrel to wear more slowly (albeit, admittedly, requiring a slower rate of fire because the gasses stay compressed and hot for longer)
Has this idea been tried? Why did it not catch on?

  1. 2 weeks ago
    Anonymous

    KISS

    • 2 weeks ago
      Anonymous

      FPBP. Also you run the risk of overpressuring and blowing shit up if it somehow doesnt burn exactly how you expect it to. What if the ammo is tossed around a whole lot and the faster propellant gets mixed in with the rest? What if there is a mistake in production and the mix isnt done properly? How do you even test something like this to make sure it is dont properly? How are you going to design a recoil system that isnt going to fucking explode?

      Its solving a problem that doesnt exist. You are not losing that much by losing pressure down the barrel but trying to save it is going to cause a LOT of explosions.

      • 2 weeks ago
        Anonymous

        Of course it will blow up if it breaks up. But, it could still be ok:
        Firstly, such a cartridge would probably be meant neither for a main rifle (because of the heavier barrel and the muzzle blast) nor for a machinegun (due to the barrel heating up more). It could work better in an anti-materiel rifle where these two downsides are not as big of a concern.
        Secondly, the actual rockets that are used both in normal rocket launchers like the RPG-7 or the gyrojet ammo, would have the same problem.
        So, thirdly, I assume they reinforce the solid propellant, turning it into a composite of some sort, perhaps stitching it to the walls.
        As for testing, it is the same thing as all expendable munitions --- you randomly test some and expect the others to behave the same way.

        • 2 weeks ago
          Anonymous

          >Secondly, the actual rockets that are used both in normal rocket launchers like the RPG-7 or the gyrojet ammo, would have the same problem.

          Rockets dont rely on pressurized gasses propelling a solid mass of lead down a tube. Its propulsion comes from the burning of propellant IN a tube venting gas out the rear. Its a huge difference. It also layers propellants by depth in the tube and not a radius from the middle to outside like is suggested if they are layered at all.

    • 2 weeks ago
      Anonymous

      shut up retard boomer

  2. 2 weeks ago
    Anonymous

    Before modern mganum handgun powders like H110 were a thing, reloaders would load a small charge of fast burning powder below the main charge of slower burning powder to do exactly this.

    • 2 weeks ago
      Anonymous

      Yeah, and they blew themselves up on a regular basis. Duplex loads lead to unpredictable pressure spikes and are a bad bad idea.

      • 2 weeks ago
        Anonymous

        They're a fine idea if you have a machine that can precisely and reliably give you a consistent load each time, solid rocket motors are designed this way

        they're a dumb meme for handloads, yeah

    • 2 weeks ago
      Anonymous

      Did they (temporarily) isolate the faster burning powder from the slower burning one in any way? Otherwise I don't see why all the powder would not ignite at the "same" time, meaning the fast burning one would burn first. Which is why I thought going with a solid propellant would be a good idea, so one propellant isolates the other until it burns up.

      • 2 weeks ago
        Anonymous

        This only worked with highly compressed charges and even then was very dangerous, see

        Yeah, and they blew themselves up on a regular basis. Duplex loads lead to unpredictable pressure spikes and are a bad bad idea.

        which is also the reason nobody does it anymore.

  3. 2 weeks ago
    Anonymous

    All of modern powder tech has been focused on flattening out the pressure curve. If it were possible it would have been done.

  4. 2 weeks ago
    Anonymous

    You see this with bigger guns, the grain size and shape of the propellant modulates pressure.

    • 2 weeks ago
      Anonymous

      >because the powder does not start burning faster while the bullet does accelerate.
      False.
      This is why some powders are shaped like small hollow sticks or "donuts". As the powder grain burns its surface area increases.
      Another workaround is duplex or triplex loads, like the original triplex load for .454 Casull.

      It's most obvious for things like artillery, naval guns, etc, but it applies to small cartridges as well.

      • 2 weeks ago
        Anonymous

        other examples

        • 2 weeks ago
          Anonymous

          I want to chew on the forbidden bubble gum

      • 2 weeks ago
        Anonymous

        https://i.imgur.com/6HWJUtN.png

        other examples

        https://i.imgur.com/VSn9WQv.jpg

        I want to chew on the forbidden bubble gum

        see
        [...]
        [...]

        Ok, so hole in the grains are used increase in burn speed with time, I see that. But apparently they still have their limits of how much the burning accelerates with some straight holes. If you want more acceleration, you need to either make a more complex shape with voids that will be opened by the combustion and start burning, or you need to change propellant. So why not make a cartridge, as

        They're a fine idea if you have a machine that can precisely and reliably give you a consistent load each time, solid rocket motors are designed this way

        they're a dumb meme for handloads, yeah

        reminded, like a solid rocket motor? Those are mass-produced fine.

        • 2 weeks ago
          Anonymous

          There's a lot of control regarding solid rocket motors. If a rocket grain cracks it changes the burn rate, if a chunk plugs the nozzle the thing pipebombs spectacularly.

    • 2 weeks ago
      Anonymous

      See:
      https://www.vihtavuori.com/tech-blog-powder-grain-shapes/
      A good point he makes is that by doing this you are also maximizing your muzzle blast.

      • 2 weeks ago
        Anonymous

        Yeah, the muzzle blast would definitely be atrocious --- basically the chamber pressure released at the muzzle, and not just a chamberful of it, but an entire barrelful. But by making the muzzle brake bigger and making it include smaller holes before it, it could be done I think.

    • 2 weeks ago
      Anonymous

      Do they make granules with holes in them so they burn faster with time? On a superficial look, it seems that pretty complex holes and voids are required for the burning speed to increase sufficiently. I don't know how they would make such granules.

      • 2 weeks ago
        Anonymous

        see

        https://i.imgur.com/6HWJUtN.png

        other examples

        https://i.imgur.com/Blgh32C.jpg

        >because the powder does not start burning faster while the bullet does accelerate.
        False.
        This is why some powders are shaped like small hollow sticks or "donuts". As the powder grain burns its surface area increases.
        Another workaround is duplex or triplex loads, like the original triplex load for .454 Casull.

        It's most obvious for things like artillery, naval guns, etc, but it applies to small cartridges as well.

      • 2 weeks ago
        Anonymous

        Powder grain extruders work like pasta extruders.
        Large grains for power usually have needle-like arrays attached to the die so that the grain comes out with perforations.

        • 2 weeks ago
          Anonymous

          >exothermighetti

  5. 2 weeks ago
    Anonymous

    The obvious problem with this idea is the giant nuclear bright deafening blasts that would be coming out of the muzzle.

    Basically if you still have high pressure when the bullet exits you are wasting energy, if you use a longer barrel to capture that energy then you have something more like a normal gun again, where pressure is way lower near the end just really long. You would also have a bunch more heat.

  6. 2 weeks ago
    Anonymous

    This is probably used in some artillery and/or naval gun prototypes. It would likely be cost prohibitive for small arms.

    • 2 weeks ago
      Anonymous

      Na i will guarantee you that pretty much nobody uses this for anything. Its far too dangerous to implement.

      • 2 weeks ago
        Anonymous

        This is how solid rocket fuel works, sort-of. Granted, the ignition of rocket fuel is more gradual than what OP is saying. Yeah, actually, it's a dumb idea and OP is retarded.

  7. 2 weeks ago
    Anonymous

    The other way to do this is through the geometry of the individual powder grains. The surface of the grain is what burns. The more surface area burning, the more gas being produced, the more pressure.

    A simple sphere gradually shrinks as it burns, so burn rate is constantly going down. This means your peak burn rate is right at the beginning, which isn't ideal.

    You could make a hollow cylinder. The outer surface burns away and shrinks. The inner surface burns away but grows. The total surface area burning stays constant, so it's a more even burn.

    You could make a cylinder with multiple holes in it in a honeycomb pattern. Now the burning surface area will actually grow, so you get peak burn rate near the end.

    Modern powders do exactly these things, although the last one is really only used in artillery and tank cannons and the like.

    • 2 weeks ago
      Anonymous

      The problem with this idea is that its practically impossible to manufacture this system to work and that no matter what shape you make a grain of gunpowder into you will -never- make it burn slow enough to maintain pressure through any meaningful distance. Modern powders burn so fast that they can and do flash instantly and any difference brought into the equation by shapes is so small its pointless to try and mix different burn rates. We use the powder we use in current firearms because its the fastest we can use safely. The only way to have some kind of two stage burning system would be to switch back to a slower burning one to match the fast one which defeats the whole fucking purpose to begin with.

Your email address will not be published. Required fields are marked *