Announcement

Collapse
No announcement yet.

Sabot physics

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Sabot physics

    not to turn this into a out of control guns vs no guns..i have a physics related question. is a sabot more efficient than a standard round of the same caliber of the projectile in the sabot?

    lets use some caliber numbers..we will use .45 for the dia of the larger caliber or sabot, and say .22 for the projectile dia in the sabot and as the smaller caliber that we are comparing

    First tell me if i am wrong...
    a sabot is lighter ...a .45 sabot generally lighter than a standard .45 round, but is still exposed to the same force of the powder. or maybe it is better to talk using PSI, dunno. therefore it may leave the barrel at a higher velocity? also once the sabot peels away..now the smaller projectile 22, has less surface area be exposed to wind resistance..so the projectile may carry further?

    now if all of this is true..which it may not be..then if you put the same charge of powder in the 45 firing the sabot and the 22 standard..what would the terminal ballistics look like...would there be any advantage at all..to either..

    just curious
    "Good judgment comes from experience, and often experience comes from bad judgment" R.M.Brown

    My shop tour www.plastikosmd.com

  • #2
    Well, "efficient" isn't necessarily the term you're looking for, I think. But you're right on the later part- the velocity imparted by the larger powder charge (relatively speaking in relation to the projectile size) but the reduced wind resistance of the smaller projectile.

    Basiclly, if you reduce the weight of the projectile (all else being equal) the same energy will drive it to higher speeds. (There used to be a plastic-bullet round called the "Thunderzap". It'd leave the barrel of even a snub-nose .38 at over 2,000 fps! But the projectile weight was so little, that after just fifty yards or so, the bullet was no longer dangerous, and after eighty or so, could be caught with your bare hands. But at phone-booth ranges, I guess it made a nasty, almost contact-distance-shotgun style wound.)

    So yes, if you had a lighter, saboted bullet in a larger shell, you'd get higher velocities from the same chamber pressure- if that's what you meant by "efficient".

    But on the other hand, since we're talking about bullets, after all, if you're talking "terminal performance", the bullet may well be going faster, but being lighter it can't carry as much energy. The classic .45 vs. 9mm argument of "light bullet going fast" versus "heavy bullet going slow".

    There's lots of variables though; a bullet half the weight but twice as fast carries roughly the same energy- though the lighter bullet tends to have better aerodynamic properties, and the faster speed gives it a "flatter" trajectory, etcetera and ad nauseum.

    So there are advantages. But really, there's such a wide range of cartridges available, it's usually easier and cheaper just to switch to a different round if you need different performance. (.45 ACP not powerful enough? You could hotrod it into something like the .45 Win Mag, but really, why not just get a .44 Magnum? .38 Special not hot enough? Grab a .357 Magnum. Still not enough? Find a .357 Maximum. And so on. )

    Doc.
    Doc's Machine. (Probably not what you expect.)

    Comment


    • #3
      thanks doc...i guess what i am looking for would be the performance of a sabot say 45 cal with a 22 cal projectile compared to a 22 cal with the same powder charge.
      guessing i would say the 22 alone may leave at a higher velocity, as the weight of the sabot+projectile would be a bit more than the 22 alone...but what happened to all that extra force gained by the increased surface area of the 45? or is it a wash...one with higher psi but less surface, other with more surface but less psi. what if we make the sabot+projectile weigh the same as the 22 alone..would we see equal performance?

      all this from watchin a stoopid tank show on discovery
      scott
      "Good judgment comes from experience, and often experience comes from bad judgment" R.M.Brown

      My shop tour www.plastikosmd.com

      Comment


      • #4
        Think of trying to hit a home run with a whiffle ball.
        Lynn S.

        Comment


        • #5
          I would think the 22 sabot round would leave the muzzle at a higher velocity of a 22 since you have a greater charge and larger diameter and, most likely, a longer barrel. The barrel has to account for some too (it adds resistance, yes, but the projectile will feel a force until it leaves the muzzle, at which point it begins to slow down).

          I don't know much about guns, but from a simplistic analysis the 22 sabot would be faster than the normal 22 and faster than the 45.

          Like doc said, E = (1/2)mv^2 (or at least thats a good approximation at low speeds) so increase in velocity will carry more energy than just increasing the mass. On the other hand, the aerodynamics depends on mass and cross sectional area. Even something with very tiny cross sectional area can have a low terminal speed while something slightly larger in cross sectional area can have a higher terminal speed. Like trying to hit a homerun with a ping-pong ball (a wiffle ball has holes that you'd have to take into account) vs hitting it with a baseball. The baseball is larger but more massive and travels better through air than the ping-pong ball does.

          So ... i dunno with the aerodynamic part

          Comment


          • #6
            I want to reply, but I'm afraid I'll get in trouble
            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

            Comment


            • #7
              Modern Battle Tank Sabotted Projectiles

              The modern battle tanks fire sabot projectiles for several reasons. First, the explosively drive reactive armor used on tanks, causes the standard high explosive (HE) shaped charges (Monroe Effect) to be effectively defeated. Secondly, the armor has gotten so thick that other HE rounds such as the Squash Head have little or no effect either.

              To come up with a solution that will be able to defeat the modern battle tank, the Kinetic Energy (KE) penetrator was developed. This is also called the long-rod penetrator. They are effective "metal darts" that are fired from the tank's main gun in a sabot package. (This is why the tank's main gun is a smooth bore and not rifled.) The sabot is needed for several reasons. First the "dart" has stablizing fins that do not lend themselves to being fired down a barrel. Also, the KE penetrator is made of very heavy metal, depleated uranium and/or tungsten carbide. The be effective, these penetrators must have a large length to diameter ratio, making them very long. Again the sabot is used to house these very long projectiles. These sabotted projectiles are fired and being that they are light compared to the HE ammunition, they have very large kinetic energy. The energy equation (Energy = 1/2 x mass x velocity squared), with the squared velocity term means that if you double the velocity of the projectile, you quadruple the energy!

              The muzzle velocity of the KE pentrators is in the 6,000 ft per sec range so the time of flight to the target is very short. This velocities, combimed with the mass of the projectile, have the effect of striking the target with several millions of joules of energy. I have seen pictures of a tank turret laying next to the tank with a KE penetrator hole in both sides of the turret. The penetrator passed through the turrent and set off all of the ammunition stored in the turret, blowing the turret off the tank.

              Bill
              Bill

              Being ROAD KILL on the Information Super Highway and Electronically Challenged really SUCKS!!

              Every problem can be solved through the proper application of explosives, duct tape, teflon, WD-40, or any combo of the aforementioned items.

              Comment


              • #8
                ________________________________________
                yea.. assume same barrel length....im just tryin to wrap my head around something like

                55 gr unique with a 22 cal round that is same weight of the 22 cal projectile that is fired using a 45 cal sabot...same 55 gr charge..

                no doubt
                45 sabot..lower pressure
                22 plain .. higher pressure

                force should be about the same tho??

                45 sabot...more area, less pressure
                22 plain more pressure..less area

                are end ballistics about the same?

                thanks for entertaining me
                scott
                "Good judgment comes from experience, and often experience comes from bad judgment" R.M.Brown

                My shop tour www.plastikosmd.com

                Comment


                • #9
                  Awesome thread. I was a crewman in an M1A1 Abrams. I loved that machine.

                  A .22 projectile fired out of a .45 would move faster, but since the .22 projectile is not engaging the rifling, it will likely be extremely unstable in flight. Sabots need fins to have a stable flight. Some rifled tank guns fire sabots, but they have bearing in the sabot to allow the projectile to "slip"; spinning much slower than a conventional round.

                  The Army experimented with smoothbore sabot rifles in the early 1970s. They were getting 10 foot groups at 600 yards.

                  The Army has sabot round for the .50 BMG, and they work, but there's just not enough demand in the civilian world for someone to put the r&d into a sabot for common civilian guns. (not many of us own .50 BMG rifles)
                  Last edited by Lee in Texas; 08-27-2007, 07:32 PM.

                  Comment


                  • #10
                    Is this in a classroom?

                    Comment


                    • #11
                      Remington has a line of sabot cartridges by the trade name of accelerator . I believe they still produce the 30-06 .22 cal. and the 30-30 .22 cal accelerator cartridges.
                      I believe the 30-06 has a muzzle velocity of almost 4100 fps, and the 30-30 accelerator was listed at 3400 fps . I don't believe that they really ever caught on that well, although I will be the first to admit that I haven't done a lot of research on the subject. A quick search for these rounds should shed more light on the subject.
                      Home, down in the valley behind the Red Angus
                      Bad Decisions Make Good Stories​

                      Location: British Columbia

                      Comment


                      • #12
                        50 SLAPT round



                        Tungsten sabot is about 30 caliber

                        Comment


                        • #13
                          They also have a DU "Silver Bullet" round much like the Abrams anti-tank round, scaled down for the 20mm "Bushmaster" automatic cannon, as used on Bradleys and the like.

                          I think the problem with the "Accellerator" round is that it's a solution to an unasked question. As I said earlier, most times when you need different ballistic performance, it's easier to simply switch to a different caliber/cartridge. At least as far as handguns and rifles go, a saboted slug among other things will have a significantly different flight trajectory- meaning your sights, if zeroed with the weapon's normal ammo, will be off- perhaps wildly so- with the lighter/faster round.

                          A 3200fps .22 out of a .30-30 is going to hit nowhere near the same spot as the rifle's sights, if set for it's regular cartridge. It'd be easier here to just switch over to something firing a conventional .223- a bit slower, but probably more accurate.

                          Doc.
                          Doc's Machine. (Probably not what you expect.)

                          Comment


                          • #14
                            thank you for the link willy, i wish he gave more load data..then i could just extrapolate from say the 30 carb. sabot to the smaller caliber with the same powder load out of a 10" TC. guess that will be as close as im gonna get for an answer!

                            love the 50 IO


                            i agree doc...the more choices the better....i was just watchin too much TV and was stumped on the answer

                            scott
                            "Good judgment comes from experience, and often experience comes from bad judgment" R.M.Brown

                            My shop tour www.plastikosmd.com

                            Comment


                            • #15
                              I vaguely remember seeing shotgun sabot rounds somewhere. But like Doc says, there's not a big market for them, unless you're hunting Cape Buffalo.
                              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

                              Comment

                              Working...
                              X