Bullet Tumble
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Stress_Test
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I read a book called "American Rifle" that had a chapter about the M16. Apparently, some of the early M16s were mistakenly produced with a ridiculously slow twist rate, like 1 in 20 or something. This meant that the bullets were basically wobblin' goblins in flight, and when they hit a bad guy, the bullet would immediately tumble out of control, creating major wound trauma. This lead to some exaggerated claims of the 5.56 round's lethality. (I guess it would be pretty lethal but the accuracy would suck).
So the book claimed. I haven't heard this info before, so if someone can confirm with another source that'd be good.
Anyway, to the OP, it looks like a tumbling bullet CAN produce extreme damage, but in the example above, the high velocity of the 5.56 was also a factor.
PS: I've wanted to try this if I could somehow get a really slow twist rate barrel and then shoot 77 grain .223 rounds and see what happens...
So the book claimed. I haven't heard this info before, so if someone can confirm with another source that'd be good.
Anyway, to the OP, it looks like a tumbling bullet CAN produce extreme damage, but in the example above, the high velocity of the 5.56 was also a factor.
PS: I've wanted to try this if I could somehow get a really slow twist rate barrel and then shoot 77 grain .223 rounds and see what happens...
ConstitutionCowboy
member
If I remember what I heard correctly, the 5.56 bullets didn't actually tumble, they wobbled. Upon entering an enemy, then they would tumble around causing much damage.
I also heard that the "less lethality" of the 5.56 was meant to only wound enough to incapacitate thereby causing one or two more soldiers to help the wounded man off the battlefield. 'Course that is only effective against an army that cares enough about fallen soldiers to carry them off the battlefield to the aid station.
So, there you have two opposing "views" of how the 5.56 is - or was - supposed to function. Either view is probably as bogus as the other view is. I don't really know the truth, but that's what I heard in the 60's and 70's. I'm still confused about the 5.56. I prefer and shoot the .308.
Later on this afternoon, I'll be cleaning my 22LR pistol that I'm breaking in (refer to post #7) and report on the leading and accuracy.
EDITED TO ADD:
Sorry, Stress Test. I didn't read your post before I posted my - er same as your - comment.
Woody
I also heard that the "less lethality" of the 5.56 was meant to only wound enough to incapacitate thereby causing one or two more soldiers to help the wounded man off the battlefield. 'Course that is only effective against an army that cares enough about fallen soldiers to carry them off the battlefield to the aid station.
So, there you have two opposing "views" of how the 5.56 is - or was - supposed to function. Either view is probably as bogus as the other view is. I don't really know the truth, but that's what I heard in the 60's and 70's. I'm still confused about the 5.56. I prefer and shoot the .308.
Later on this afternoon, I'll be cleaning my 22LR pistol that I'm breaking in (refer to post #7) and report on the leading and accuracy.
EDITED TO ADD:
Sorry, Stress Test. I didn't read your post before I posted my - er same as your - comment.
Woody
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Stress_Test
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That's okay, you pointed out something that I should've said more clearly, that the bullet wasn't actually tumbling in flight, just that it was unstable in flight. The tumbling happened after impact.
230RN
2A was "political" when it was first adopted.
Stress_Test remarked,
The spin required to stabiize a bullet varies with the density of the medium through which it is passing. More dense materials, such as flesh, require more spin to stay point-on. But the twists we find in most firearms are designed to be for that ammunition in air. So they tend to destabilize when entering other materials.
Like flesh.
How much of this "tendency" is the subject of much experimentation in Ordnance Departments around the world.
For more dense target materials, "the spin as worked out for air must be multiplied by the square root of a number found by dividing the density of the material in question by the density of air." (Hatcher's Notebook, p 556-557 and following.)
This, bearing in mind that there are no sharp cutoffs in twist calculations, such as the "Greenhill Formula," for estimating twist requirement for a particular bullet. In general, it's better to have a faster twist so that longer (hence heavier) bullets can be used if necessary.
Another destabilization factor is the "arrow effect." I understand, but cannot cite offhand, that certain variations of combloc bullets had the points virtually hollow, with the main weight of the core toward the rear of the bullet to encourage tumbling in denser materials.
Like flesh.
Point shape is also a consideration.
Yet another major factor is the density of the bullet. A greater twist is required for less dense bullets. An aluminum bullet of the same size and shape of a gilding-metal clad lead bullet would have to have twice the spin required for stabilization in air. (Op cit, p 556)
The new developments in 5.56 NATO bullets are a result of experimentation to determine the best compromises between accuracy at range and terminal ballistics (including armor penetration and destruction of tissue) out of the short-barreled M4 carbine.
Terry, 230RN
The spin required to stabiize a bullet varies with the density of the medium through which it is passing. More dense materials, such as flesh, require more spin to stay point-on. But the twists we find in most firearms are designed to be for that ammunition in air. So they tend to destabilize when entering other materials.
Like flesh.
How much of this "tendency" is the subject of much experimentation in Ordnance Departments around the world.
For more dense target materials, "the spin as worked out for air must be multiplied by the square root of a number found by dividing the density of the material in question by the density of air." (Hatcher's Notebook, p 556-557 and following.)
This, bearing in mind that there are no sharp cutoffs in twist calculations, such as the "Greenhill Formula," for estimating twist requirement for a particular bullet. In general, it's better to have a faster twist so that longer (hence heavier) bullets can be used if necessary.
Another destabilization factor is the "arrow effect." I understand, but cannot cite offhand, that certain variations of combloc bullets had the points virtually hollow, with the main weight of the core toward the rear of the bullet to encourage tumbling in denser materials.
Like flesh.
Point shape is also a consideration.
Yet another major factor is the density of the bullet. A greater twist is required for less dense bullets. An aluminum bullet of the same size and shape of a gilding-metal clad lead bullet would have to have twice the spin required for stabilization in air. (Op cit, p 556)
The new developments in 5.56 NATO bullets are a result of experimentation to determine the best compromises between accuracy at range and terminal ballistics (including armor penetration and destruction of tissue) out of the short-barreled M4 carbine.
Terry, 230RN
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ConstitutionCowboy
member
Finally! My Internet is back up! Two days down! AGGAHHH!
Referring back to Comment #7, the test/ break-in on my new 22LR pistol - a Chiappa 1911-22 - continued Friday AM and the accuracy was much improved. After fifty rounds in this second firing, there was very little lead build-up. I suspect there was some sort of build-up in the barrel prior to my initial 150 rounds. I guess it's paramount that you especially, THOROUGHLY, clean the barrel on your new guns before you do any firing, though I've never had such a build-up in any of the new guns I've ever bought previously.
My conclusion is that once the rifling gets loaded up with lead (or copper), you loose spin and therefore, accuracy. I do believe it could also create higher pressures in the chamber/barrel to the point of possible structural failure.
Referring back to Comment #7, the test/ break-in on my new 22LR pistol - a Chiappa 1911-22 - continued Friday AM and the accuracy was much improved. After fifty rounds in this second firing, there was very little lead build-up. I suspect there was some sort of build-up in the barrel prior to my initial 150 rounds. I guess it's paramount that you especially, THOROUGHLY, clean the barrel on your new guns before you do any firing, though I've never had such a build-up in any of the new guns I've ever bought previously.
My conclusion is that once the rifling gets loaded up with lead (or copper), you loose spin and therefore, accuracy. I do believe it could also create higher pressures in the chamber/barrel to the point of possible structural failure.
I've had the same thing happen with a well maintained gun. I can fill the grooves with lead in my 22 pistol just by shooting a brick of unjacketed rounds like Blaser without cleaning it. They'll start to keyhole if I keep it up long enough. Much the same experience as the OP - I can push lead shavings out of the barrel with a brush. The barrel is in perfectly good shape - not rusted or rough. In fact it's very accurate until the grooves get clogged up. On the other hand, I can put a whole box of jacketed rounds through it - like the Federal 525 bulk pack for example - with no ill effects.
ConstitutionCowboy
member
Flopsweat said:
Just a somewhat minor correction: Federal 525 is plated, not jacketed, like the CCI plated stuff. The copper plating does help tremendously, though.
Woody
Fair enough. I give people grief over clip vs. magazine so I'm in no position to birch.
ConstitutionCowboy
member
We're on the same plank.
Woody
Woody
exavid
Member
I'm surprised that a .22 pistol would lead up that easily. I shoot Bullseye every Monday eveningat my club. We fire about 100 rounds per Monday, 90 on targets and ten for warm up. I clean my Buckmark about once every four weeks. The pistol does get a good bit of soot and powder residuals but no lead in the barrel. I also shoot Adult Smallbore in the winter where we fire about 80-100 rounds each Wednesday for a six month season. I don't clean the rifle very often either but it doesn't lead up and will shoot a 1/2" group all day long at 50' with my old eyes. I use Federal Target Grade ammo in the cubical white box purchased at WalMart. I usually buy at least ten boxes at a time hoping they're all the same batch. That way performance is pretty consistant.
ConstitutionCowboy
member
I tend to agree wit you, exavid. I'm wondering if an over heated barrel can cause the lead build-up as well as a fouled or dirty barrel. My first run of 150 rounds a couple weeks ago was rather rapid - the 150 rounds in half an hour.
Woody
Woody
mr.trooper
Member
A 22LR can achieve 11 - 12" of penetration in Ballistics gel from a 3 - 4" barrel.
SUB OPTIMAL, sure... But a JOKE? Far from it.
One shot stops are absolutely possible with a .22LR handgun - both physical and psychological stops.
Sure, it MAY take several minutes to bleed out from a center mass hit from a .22 - or you could be unconscious in a few seconds when it shreds an artery or perforates your heart. The reason .22 is not recommended for primary carry is not that it wont work, or even that it is unlikely to work, but rather simply to err on the side of caution.
Logic is a two way street; just because you can't count on a .22 to immediately incapacitate DOES NOT mean you can count on it to fail. Many a person who knows that to be true is no longer here to interject. That is the furthest thing from a joke.
SUB OPTIMAL, sure... But a JOKE? Far from it.
One shot stops are absolutely possible with a .22LR handgun - both physical and psychological stops.
Sure, it MAY take several minutes to bleed out from a center mass hit from a .22 - or you could be unconscious in a few seconds when it shreds an artery or perforates your heart. The reason .22 is not recommended for primary carry is not that it wont work, or even that it is unlikely to work, but rather simply to err on the side of caution.
Logic is a two way street; just because you can't count on a .22 to immediately incapacitate DOES NOT mean you can count on it to fail. Many a person who knows that to be true is no longer here to interject. That is the furthest thing from a joke.
exavid
Member
Yeah those .22s are really worthless for SD. Get real!
If you can place your shots accurately the venerable .22LR is effective. Just Robert F. Kennedy. Oh yeah, you can't ask him because he was assassinated with an old Iver Johnson .22 revolver.
How about this farmer?
http://articles.nydailynews.com/2012-09-04/news/33587269_1_home-intruder-intruder-police-earl-jones
If you can place your shots accurately the venerable .22LR is effective. Just Robert F. Kennedy. Oh yeah, you can't ask him because he was assassinated with an old Iver Johnson .22 revolver.
How about this farmer?
http://articles.nydailynews.com/2012-09-04/news/33587269_1_home-intruder-intruder-police-earl-jones
exavid
Member
And how do we know that? All official accounts I can find stagte that Kennedy was hit three times with Sirhan's .22. Of course there are plenty of other possibilities, there might even have been a shooter standing on a grassy knoll in that hotel kitchen.
AethelstanAegen
Member
We know nothing of the sort, twinny. Who are "we" anyways? What was it, a shooter hidden in the podium? Sometimes it is exactly as straightforward as it is. Are you just trying to troll everyone by making us shake our heads in confusion? All your posts are like this.
Walt Sherrill
Member
It can depend on the barrel, but more often on the round itself. I had a Ruger Target Competition (Government model, slab-sided) that shot beautifully with almost everything but one brand of bulk ammo (Remington, if I remember correctly), and one brand of premium Target ammo. In both cases, the barrel would go from clean to heavily leaded in one range session of a box or two of ammo, with keyholing obvious at the end of the session. No rust or pitting in the barrel, and no use of odd ratshot rounds.
With regard to earlier comments about the effectiveness of .22 rounds:
While a lot of small caliber rounds have taken lives, a lot of them -- especially with head shots -- go under the skin and travel around OUTSIDE the skull if they simply don't hit and bounce away. If you're trying to use a .22 for self-defense, the rounds really aren't going to stop anyone unless 1) you're lucky, 2) have time to really aim well, 3) can see a good target area. A lot of gun-related confrontations don't come with those options. A .22 rifle might be a better option, but that's not easily carried or concealed.
I'll bet the emergency room docs who talk about them forgot to mention all of the far less damaging shots they've had to patch up from similar small-caliber rounds.
.
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230RN
2A was "political" when it was first adopted.
^
Thanks. I neglected to mention that. I, too, use standard velocity or the high-speed "standards" and have never had a problem with leading. The picture is probably different if you habitually use souped up rounds.
A long time ago, when the Ordnance Department was investigating cupro-nickel jacket fouling in the GI rifles, the fouling mainly occured near the muzzle, "not where the pressure and temperature was highest, but where the bullet was fastest."
Perhaps there's a lesson there with respect to lead or plated .22LR bullets. Try to run 'em out faster than the competition's rounds, and by gum golly, you get leading.
And there are other variables, such as the lube on the bullets --different kinds of wax, moly di versus graphite, different lead alloys, etc. (In general, alloying anything with a base metal lowers the melting point.)
And, let's face it, if you're going to shoot cast bullets in center-fires at much over, say, approximately, more-or-less, kinda-sorta 1100 feet per second, you really ought to use copper gas checks on your lead bullets or you will get severe leading from the bases of the bullets getting all melty and squooshy on their way up the barrel.
And you still get leading anyhow.
A lesson there, too?
Terry, 230RN
Thanks. I neglected to mention that. I, too, use standard velocity or the high-speed "standards" and have never had a problem with leading. The picture is probably different if you habitually use souped up rounds.
A long time ago, when the Ordnance Department was investigating cupro-nickel jacket fouling in the GI rifles, the fouling mainly occured near the muzzle, "not where the pressure and temperature was highest, but where the bullet was fastest."
Perhaps there's a lesson there with respect to lead or plated .22LR bullets. Try to run 'em out faster than the competition's rounds, and by gum golly, you get leading.
And there are other variables, such as the lube on the bullets --different kinds of wax, moly di versus graphite, different lead alloys, etc. (In general, alloying anything with a base metal lowers the melting point.)
And, let's face it, if you're going to shoot cast bullets in center-fires at much over, say, approximately, more-or-less, kinda-sorta 1100 feet per second, you really ought to use copper gas checks on your lead bullets or you will get severe leading from the bases of the bullets getting all melty and squooshy on their way up the barrel.
And you still get leading anyhow.
A lesson there, too?
Terry, 230RN
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