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The bullet is yawing heavy if not tumbling. It will keyhole a target.
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Quoted: Seriously, even my old posts werent that dumb. First there was the comment of 5.45x45.....then he said the bullet tumbles out of the barrel, and stabilizes down range.... View Quote ive probably used the wrong terms and explained it wrong, maybe someone who actually know wtf will chime in. |
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The bullet is yawing heavy if not tumbling. It will keyhole a target. https://www.AR15.Com/media/mediaFiles/369185/Screenshot_2018-02-19-21-08-02-458016.JPG https://www.AR15.Com/media/mediaFiles/369185/Screenshot_2018-02-19-21-08-43-458017.JPG https://www.AR15.Com/media/mediaFiles/369185/Screenshot_2018-02-19-21-09-04-458019.JPG https://www.AR15.Com/media/mediaFiles/369185/Screenshot_2018-02-19-21-03-09-458023.JPG https://www.AR15.Com/media/mediaFiles/369185/Screenshot_2018-02-19-21-09-55-458031.JPG View Quote |
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Quoted: That's real fucking dumb sir. That's called keyholeing and it's not a feature of the rifle. Bullets don't tumble end over end and then magically stabilize. Don't worry guys, it's a fucking commie gun! Keyholeing and tumbling are features of the guns! View Quote View All Quotes View All Quotes Quoted: That's real fucking dumb sir. That's called keyholeing and it's not a feature of the rifle. Bullets don't tumble end over end and then magically stabilize. Don't worry guys, it's a fucking commie gun! Keyholeing and tumbling are features of the guns! This is what you quoted, and said was dumb. 5.45x45 has a very high yaw rate. It stabilizes further away from the muzzle. (I believe) Read more post less. |
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I'm now just in this thread to see who ends up looking like a dumb ass. With the replies that have been posted, there is no way for someone to not look like a dumb asshole at this point
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Quoted: Never said that. This is what you quoted, and said was dumb. That is the quote I replied to, and posted a vid to show what happens prior to bullet stabilization Read more post less. View Quote Inside the M4 Carbine (4K UHD) Attached File Attached File Attached File Attached File |
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5.45x45 has a very high yaw rate. It stabilizes further away from the muzzle. (I believe) View Quote never mind. pro-tip: spend less time in GD, and more time reading quality material. here is a start --> https://www.amazon.com/Modern-Exterior-Ballistics-Robert-McCoy/dp/0764338250 |
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I believe the longer skinner bullets tend to do it more.
It has to do with the center of gravity of a round. Ever seen a football start out kind of wobbly then go into a perfect spiral? |
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wat...... so you think its just tumbling end over end and then magically stabilizes itself downrange View Quote View All Quotes View All Quotes Quoted:
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5.45x45 has a very high yaw rate. It stabilizes further away from the muzzle. (I believe) This is not the say the demonstrated firearm and ammo are not showing tumbling. |
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Yawing a bit is not the same as tumbling. As it spins around its axis the tail of the bullet and the nose rotate around the long axis. With few more milliseconds of spin it settles down. This is not the say the demonstrated firearm and ammo are not showing tumbling. View Quote |
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That's the dumbest thing I've ever fucking read. View Quote View All Quotes View All Quotes |
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5.45x45 has a very high yaw rate. It stabilizes further away from the muzzle. (I believe) View Quote Those bullets were hitting the muzzle device on the way out I believe. It looked from the video like the brake was moving somewhat independent of the barrel. |
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So Russian drunks still shank a few guns on their shift, who knew? Having some 5.56 AK's their shit accuracy is overstated. Shit ammo has more to do with it. Even my horribly canted wasr-3 is decently accurate, it just doesn't work great. My SLR-106FR on the other hand is awesome in every aspect. I wish I could have bought a Vepr-IV RPK or a cheap Beryl/Archer.
Edit: I'm no AK apologist either. I bought a unfired 106 CR that Arsenal absolutely refused to fix that was much shittier than the wasr-3. It was the most accurate of the three, but would FTEx over half the time. So fuck Aresenal and anyone who makes sub-standard guns. I enjoy all my non-ar rifles. AK's aren't magic or horrible in my experience. |
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The effect is called Fleet Yaw, and is present in all spitzer rifle projectiles tested by the US government:
"Yaw is the angle the centerline of the bullet makes to its flight path as the projectile travels down range (Figure 4). Although the bullet spins on its axis as a result of the barrel’s rifling, that axis is also wobbling slightly about the bullet’s flight path. Yaw is not instability; it occurs naturally in all spin-stabilized projectiles. However, bullet yaw is not constant and rifle bullets display three regions of significantly different yaw (see Figure 5). Close to the muzzle, the bullet’s yaw cycles rapidly, with large changes of angle in very short distances (several degrees within 1-2 meters range). Eventually, the yaw dampens out and the bullet travels at a more-or-less constant yaw angle for the majority of its effective range. Then, as the bullet slows, it begins to yaw at greater and greater angles, until it ultimately destabilizes." http://www.dtic.mil/dtic/tr/fulltext/u2/a519801.pdf How the testing was done: https://docs.google.com/viewer?url=http://www.dtic.mil/dtic/tr/fulltext/u2/a458409.pdf Fleet Yaw was the reason M855A1 was designed, as it greatly effected performance of the m855 projectile: Typical AK74 accuracy with 5.45 7n6 surplus ammo was around 1.75-2.5 moa in tests I've seen. I'm not concerned. |
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Quoted: Seriously, even my old posts werent that dumb. First there was the comment of 5.45x45.....then he said the bullet tumbles out of the barrel, and stabilizes down range.... View Quote That one actually made me laugh, considering you were absolutely right, and if it was him saying it, they'd have shut the fuck up and praised him, considering what his job title is. |
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Just came here to post that the dude at the end of the video runs like a girl. That is all
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Interesting...Doesn't happen here, or do only Russian calibers tumble when exiting the muzzle and eventually self stabilize? Must be a feature that enhances fragmentation. View Quote any non-uniformity of gas pressure when the projectile egresses the barrel will impart an effect called epicyclic swerve. basically, a pressure imbalance at the crown "pushes" one side of the bullet slightly, which when combined with the projectile rotation (imparted by the rifling) causes a corkscrew motion during flight. this is much more common than you may realize. in fact, it is one reason a rifle may be more accurate at a distance than up close; the amplitude of the epicyclic swerve decays as the projectile is in flight. for some types of bullets, the result of the cyclic yaw "improving" at long distances is that the helix gets tighter -- counter-intuitively improving accuracy and precision at greater distances. there are at least two components to minimizing epicyclic swerve: the quality of the muzzle crown and the uniformity of the bullet base. these two aspects define the gas interface just as the projectile exits the barrel. the homogeneity of the gas interface just as the bullet leaves the barrel is CRITICAL to the accuracy of a single round and the precision of a group of rounds (consistency). homogeneity means the relief of the gas pressure at the muzzle should be EXACTLY equal in every direction. any distortion in this area pushes the base of the bullet slightly in one direction, leading to (and/or exacerbating) epicyclic swerve due to the slight aerodynamic lift in the initial direction the base was tilted. this is one reason that you don't stand a rifle on it's muzzle, as any damage to the crown results in the aforementioned pressure imbalance. as for the projectile, the uniformity of the bullet base can be improved via OTM construction -- that is, drawing the copper jacket from the base up rather than the tip down. this results in a far more uniform base. the better you can control the final (parting) interface between the muzzle crown and the bullet base, the better the system accuracy well be. incidentally, the lot to lot (aka fleet) variation of M855 is so high because the steel penetrator used in the SS109 projectile only needs to be off center by 0.001" and the accuracy of a given M855 round goes to shit thanks to epicyclic swerve the whole way to the target. and the next round fired will have different characteristics as well. note that epicyclic swerve results in a very, very shallow yaw angle which dampens out in something on the order of 1000-2000 bullet diameters downrange. epicyclic swerve WILL NOT result in keyholing at the target; keyholing is the result of dynamic instability of the projectile -- for example insufficient rotational velocity. ps everything you need to know is in McCoy, R. L., "Modern External Ballistics, The Launch and Flight Dynamics of Symmetric Projectiles" http://kuulapaa.com/onewebmedia/viipotus_2_800.jpg https://www.youtube.com/watch?v=KH9SCbCBHaY View Quote Brian Litz has had a long standing challenge for anyone who can actually demonstrate what you are talking about happening. But nobody has been able to do so. Stabilisation improves as a result of velocity dropping faster than the rpms, but "accuracy" does not |
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I must say i like it. the keyhole can be solved with bullet weight or twist- easy fix. but they are modernizing.
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Some people might benefit from reading the Army Research Lab's study entitled Small Caliber Projectile Impact Angle Determined from Close Proximity Radiographs.
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Some people might benefit from reading the Army Research Lab's study entitled Small Caliber Projectile Impact Angle Determined from Close Proximity Radiographs. View Quote Bullets do not flip, end over end and then magically stabilize. They may wobble, but the LAV video clearly shows a bullet flipping vertically end over end....that's not fleet yaw, that's tumbling. The OP also learly shows bullets keyholeing. |
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That thread was awesome. But what's a JDAM arclight? View Quote View All Quotes View All Quotes Quoted:
Quoted: lol. Can we take another moment to appreciate we did a JDAM arclight just show the Russians how huge our dick is. A JDAM arclight. Shit. Greatest timeline ever. But what's a JDAM arclight? ARCLIGHTs are B52 Mag Dumps. |
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JDAMs are precision guided munitions. ARCLIGHTs are B52 Mag Dumps. View Quote View All Quotes View All Quotes Quoted:
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Quoted: lol. Can we take another moment to appreciate we did a JDAM arclight just show the Russians how huge our dick is. A JDAM arclight. Shit. Greatest timeline ever. But what's a JDAM arclight? ARCLIGHTs are B52 Mag Dumps. |
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Never said that. This is what you quoted, and said was dumb. That is the quote I replied to, and posted a vid to show what happens prior to bullet stabilization Read more post less. View Quote View All Quotes View All Quotes Quoted:
Quoted: That's real fucking dumb sir. That's called keyholeing and it's not a feature of the rifle. Bullets don't tumble end over end and then magically stabilize. Don't worry guys, it's a fucking commie gun! Keyholeing and tumbling are features of the guns! This is what you quoted, and said was dumb. 5.45x45 has a very high yaw rate. It stabilizes further away from the muzzle. (I believe) Read more post less. Bullet Stabilization and Barrel Twist ETA: Sorry @jon101st, meant to quote joglee or Greenhorn or any of the other retards that can't read. |
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Subjects of Glorious Mother Russian were able for the first time to see the internals of this radical new gun...
An AK-74 with a Free-floated handguard, and a top-cover mounted rear sight... Sorry Ivan, its the same gun Kalashnikov designed 60+ years ago, in a smaller caliber, which they adopted almost 45 years ago, with some add-ons from Tapco and the Valmet. Granted, the M4 is just an M16, which is an AR-15 in full auto, and isn't new either, but we don't pretend it is. |
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Yeah, that takes some really interesting physics to do that. View Quote View All Quotes View All Quotes Quoted:
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5.45x45 has a very high yaw rate. It stabilizes further away from the muzzle. (I believe) https://www.physicsforums.com/threads/bullet-behavior-during-flight.369401/ |
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Quoted: And yet................. https://www.physicsforums.com/threads/bullet-behavior-during-flight.369401/ View Quote The bullet in LAVs video was tumbling end over end vertically. That is not fleet yaw or any other yaw. Also did you see my post of the M4? No tumbling end over end, so is 5.56 immune to "yaw" or can we just admit those bullets are beyond the norm. Even your link says bullets can fly in a helix type pattern, what the LAV video showed was the bullet flying straight, except it was flip flopping like a dolphin while flying straight, that's not a helix pattern. In a helix pattern the bullet should still be point in the right direction, just moving kind of circular down it's path of travel. What were seeing in the videos is the bullet going ass end up, down, and back around. Tell me you see the difference. |
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