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Fleet Yaw Fo' Realz


Sturgeon
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Reminds me of the stupid things people tell me at the range, that the M16 is deadly because it tumbles in flight rather than spins.  Only the AK47 really tumbles, 

 

One question on the yaw.  The AK47 unlocking sequence does not occur after a pressure drop, but at high pressure when the bullet has a few centimeters of barrel to travel.  Now say some crazy guy cuts apart an AK to show its action, and that causes the unlock sequence to time right when the bullet leaves the barrel.  You could have a small force caused by recoil being applied to the bullet in the final milliseconds of its travel in the bore.  Would it be possible the yaw seen in this bullet is caused by the modification of the weapon?

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Reminds me of the stupid things people tell me at the range, that the M16 is deadly because it tumbles in flight rather than spins.  Only the AK47 really tumbles, 

 

One question on the yaw.  The AK47 unlocking sequence does not occur after a pressure drop, but at high pressure when the bullet has a few centimeters of barrel to travel.  Now say some crazy guy cuts apart an AK to show its action, and that causes the unlock sequence to time right when the bullet leaves the barrel.  You could have a small force caused by recoil being applied to the bullet in the final milliseconds of its travel in the bore.  Would it be possible the yaw seen in this bullet is caused by the modification of the weapon?

 

Videa, that's an AK-74, and the rounds are not tumbling, they are yawing. Think of the precession of the Earth, though it's more exaggerated with the projectiles. Also, according to the Army Research Laboratory, this happens with all small arms projectiles, it's an unavoidable consequence of the turbulence generated by the uncorking process.

The unlocking sequence for the AK and AR and in fact most modern rifles all happens at relatively high pressure, relative to older rifles like the M1 Garand. This helps enhance reliability in adverse conditions. The AK in the video isn't cut apart (the top cover and top handguard have been removed), and is operating normally. Further when projectiles in the GIFs were shot, the rifles were fully assembled.

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Early AR-15's were nasty because the projo was marginally stable in atmosphere, not because it was tumbling after it left the bore. People who believe it's coming out like some kind of methed up acrobat are also the first to claim the AR "shits where it eats" and that the AK/AKM will chamber and fire 7,62 NATO because "they was in da 'Nam".

 

All gunshop/range bullshit aside-

 

That yawing is not as uncommon as one would think. An interesting study done by Julian Hatcher on the M2AP round found that it's penetrative abilities were reduced somewhat, inward of 300 yards, because the projo had not yet stabilized.

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Early AR-15's were nasty because the projo was marginally stable in atmosphere, not because it was tumbling after it left the bore. People who believe it's coming out like some kind of methed up acrobat are also the first to claim the AR "shits where it eats" and that the AK/AKM will chamber and fire 7,62 NATO because "they was in da 'Nam".

 

You have to realize that at the gun range last year when I took my wife, a guy explained quite seriously that bullets spin the opposite direction when fired in Brazil because of "cory sails effects."  It was the reason, he explained, why guns in South American have their barrels installed upside down.

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I used to work in a gunshop/surplus store.

It was like a singularity of absurdity when it came to attracting bullshitters and range-commandos.

I also get it giving museum tours. The armored tour is probably (obviously) the worst, but I'd say the MG42 on display indoors gets the widest range of myths. I think most of the time it's people just extrapolating on one feature to make up something that sounds plausible-yet-amazing to try to impress me or other visitors. My favorite one is a claim that if Germans didn't have ammo around for the '42, they'd fire blanks because Allies were scared of the noise, which was just so mind-bogglingly dumb he had to have made it up on the spot.

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I also get it giving museum tours. The armored tour is probably (obviously) the worst, but I'd say the MG42 on display indoors gets the widest range of myths. I think most of the time it's people just extrapolating on one feature to make up something that sounds plausible-yet-amazing to try to impress me or other visitors. My favorite one is a claim that if Germans didn't have ammo around for the '42, they'd fire blanks because Allies were scared of the noise, which was just so mind-bogglingly dumb he had to have made it up on the spot.

Who knows? Maybe there were instances of Germans using blank rounds as a way to distract enemy troops or cover a retreat. And with the supply situation being as dire as it was for the average German infantryman at the end of the war, maybe there were situations where they had literally nothing left. Or, given the quality of some of the SS and Volkssturm units, it's possible they didn't know the difference.

 

I can imagine the reaction, though, of some canny American NCOs when they realized that the machine-gun nest in front of them was using blanks.

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Who knows? Maybe there were instances of Germans using blank rounds as a way to distract enemy troops or cover a retreat. And with the supply situation being as dire as it was for the average German infantryman at the end of the war, maybe there were situations where they had literally nothing left. Or, given the quality of some of the SS and Volkssturm units, it's possible they didn't know the difference.

 

I can imagine the reaction, though, of some canny American NCOs when they realized that the machine-gun nest in front of them was using blanks.

I'll take it with a grain of salt, though he was insisting it was a "common tactic" and the way he was saying it made it sound dumb. I tried looking it up after the fact, and found nothing. From the way the guy was talking, it sounded like he'd seen or heard of the "don't be scurred of the MG42 noise" film and kind of just made it up. I don't get rude about that, and one of the things I like about the way they let you conduct tours lets me have a discussion. I like it, because people are more open if you try to be friendly and reasonable to someone talking face-to-face versus an internet text disagreement over "Ronsons" on the internet. To be fair, I've been humbled a few times, mostly in naval stuff, but to be fair look up USS Pennsylvania and try not to get confused right away.

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Who knows? Maybe there were instances of Germans using blank rounds as a way to distract enemy troops or cover a retreat. And with the supply situation being as dire as it was for the average German infantryman at the end of the war, maybe there were situations where they had literally nothing left. Or, given the quality of some of the SS and Volkssturm units, it's possible they didn't know the difference.

 

I can imagine the reaction, though, of some canny American NCOs when they realized that the machine-gun nest in front of them was using blanks.

 Because the BFA for the '42 is a clunky affair, and was usually kept well guarded by the local waffenmeister, lest some hamfist mount it and try to fire service loads.

 

It's not like clipping on the BFA for a '60 or M-16. You were replacing the booster assembly.

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To be fair I have a BFA barrel for the Glock that simulates recoil.  However it does not simulate the real "zing!" you hear when a bullet passes in front of your nose.  Nothing is worse than being in the wrong position in the tire house and figuring out at the last second you are in a covered arc of someone in the line.  

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Where would you find a good source for further reading regarding fleet yaw?

 

Also, watched that video basically first thing this morning, made my day. Now I want to take my 74 back to the range.

 

Almost all I know is in the post linked in the OP. It hyperlinks to another post with two documents on fleet yaw that should set you straight.

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