View Full Version : 5.56 "tumbles" in people says OLN...
I was watching OLN Wed line up of gun shows, and one had a dedication to the AR, with some interesting historical info on the AR. I forget which program it was, perhaps Shooting USA. Then they get to someone who starts discussing the 5.56. He says that many didn't trust the little bullet, but it turned out to be more effective then the bullet it replaced. :rolleyes:
That gets my attention. Then he says, the 5.56 is so effective because it "tumbles" in the target (no, he didn't say yaws and fragments but "tumbles") and the larger bullet it replaced (he never said 7.62 BTW) just made holes in people.
Wow, kinda thought knowledge base out there was better then that, and or, perhaps someone with actual knowledge of the topic screened the show for accuracy.
Anyone see that show? Might have been Shooting USA. I enjoyed the historical look at the AR (didn't learn anything, but it was nice to see the black rifles getting such credits) but had hoped that type of poor info was long gone.
That information has been going around for a very long time. My brother who served in southeast Asia in the late '60s heard that from the sergeants who trained him.
polymorpheous
05-20-11, 08:34
Wasn't there something about the original twist rate that barely stabilized the 55gr. projectile?
Was it 1:14? Then the Air Force needed it changed to 1:12? Or vice versa?
This is the story I heard anyways.
I don't know if it is true or not.
Could it be that you are being a little overly critical of what he said? I guess it depends on how you look at things.....
To me the thought of a bullet tumbling is more of a "laymens term" for yawing and fragmenting making it easier for those with little or no knowledge on the subject to understand. You also have to keep in mind that the fragmentation was the best case, however not always a given. If the bullet yaws and doesn't fragment wouldn't that simply mean it tumbled?
The orginal twist was 1/14 which made the bullets more likely to tumble or yaw.
Could it be that you are being a little overly critical of what he said?
On the "tumbling" aspect perhaps, but the the 5.56 being more effective then the bullet it replaced, no. Have heard the tumble thing many times as you all have, and as you said, perhaps an overly simple easy way to explaining terminal ballistics.
But, more effective then the bullet it replaced? No way to spin that one, it's just faulty info.
Never heard that particular bit of info before as it relates to 5.56. :bad:
On the "tumbling" aspect perhaps, but the the 5.56 being more effective then the bullet it replaced, no. Have heard the tumble thing many times as you all have, and as you said, perhaps an overly simple easy way to explaining terminal ballistics.
But, more effective then the bullet it replaced? No way to spin that one, it's just faulty info.
Never heard that particular bit of info before as it relates to 5.56. :bad:
I guess it again depends on how you look at it. Everyone knows that 7.62 is very effective, however on human targets it really excels when there is cover involved. The larger heavier mil ball round will expend most of energy well after passing through a person, unlike 5.56 which will expend all of it energy into the target. Its tough for a bullet to be good at both. I guess it really depends on how you look at it.
Doc Safari
05-20-11, 09:14
Wasn't there something about the original twist rate that barely stabilized the 55gr. projectile?
Was it 1:14? Then the Air Force needed it changed to 1:12? Or vice versa?
This is the story I heard anyways.
I don't know if it is true or not.
The version I heard:
The original M16 barrel had a 1:14 twist. This barely stabilized the bullet, which tended to tumble on impact. Early troops were very happy with this, because it caused very catastrophic wounds. If it hit you in the arm, it would take your arm off. If it hit you in the gut, it would disembowel you. Troops nicknamed the gun the "meat axe."
So in steps the military, who didn't like how that rifling twist would not stabilize tracer rounds sufficiently to meet accuracy requirements. The rifling was changed to 1:12 and the rifle and cartridge no longer had the devastating effect on targets.
I guess it again depends on how you look at it. Everyone knows that 7.62 is very effective, however on human targets it really excels when there is cover involved. The larger heavier mil ball round will expend most of energy well after passing through a person, unlike 5.56 which will expend all of it energy into the target. Its tough for a bullet to be good at both. I guess it really depends on how you look at it.
I'd say we need an expert such as Dr Roberts to comment on the above, but my understanding is the 7.62 has superior terminal performance across the spectrum regardless of how you choose to look at it, all things being equal*
*= That is comparing apples to apples of the version of the rnd.
polymorpheous
05-20-11, 09:25
The version I heard:
The original M16 barrel had a 1:14 twist. This barely stabilized the bullet, which tended to tumble on impact. Early troops were very happy with this, because it caused very catastrophic wounds. If it hit you in the arm, it would take your arm off. If it hit you in the gut, it would disembowel you. Troops nicknamed the gun the "meat axe."
So in steps the military, who didn't like how that rifling twist would not stabilize tracer rounds sufficiently to meet accuracy requirements. The rifling was changed to 1:12 and the rifle and cartridge no longer had the devastating effect on targets.
This is almost verbatim what I've read.
I didn't take too much stock in it.
Heavy Metal
05-20-11, 09:43
The version I heard:
The original M16 barrel had a 1:14 twist. This barely stabilized the bullet, which tended to tumble on impact. Early troops were very happy with this, because it caused very catastrophic wounds. If it hit you in the arm, it would take your arm off. If it hit you in the gut, it would disembowel you. Troops nicknamed the gun the "meat axe."
So in steps the military, who didn't like how that rifling twist would not stabilize tracer rounds sufficiently to meet accuracy requirements. The rifling was changed to 1:12 and the rifle and cartridge no longer had the devastating effect on targets.
That's what I heard too. Of course it has since been totally debunked.
Tumble, Yaw, tomato, tomatoe...whatever, its TV.
The twist rate was changed from 1:14 to 1:12 very early on, as 1:14 would not stabilize the bullet in arctic conditions/temps.
Effective is a moving target. The 5.56 and various other assault rifles were not developed and adopted in a vacuum, or willy nilly. years of "AAR"s and combat with a .30 cal bullet at 2700 or so FPS determined it was more then needed for the vast majority of combat. It also required bigger and heavier guns to handle it.
more effective, could be a gun/cartridge combo that has sufficient terminal effects for the majority of combat engagements, but...allows for more ammo to be carried, and less user fatigue after humping the load all day, low recoil, and flat trajectories, that make for easier hits.
How effective is the 7.62 when your out of ammo?
Is that what the TV personality meant? Probably not, but then again, hes on TV, and a show that is the equivalent of Guns and Ammo magazine:rolleyes:
Bob
more effective, could be
In the context of this conversation = terminal ballistics.
a gun/cartridge combo that has sufficient terminal effects for the majority of combat engagements, but...allows for more ammo to be carried, and less user fatigue after humping the load all day, low recoil, and flat trajectories, that make for easier hits.
Which is where the AR platform and 5.56 excel to be sure, but again, not the point of what I was responding to via OLN and above.
The 5.56 appears to strike a balance (with some debate as you know...) as you outlined above nicely, but to state it's superior performer to the 7.62, to the best of my knowledge, incorrect info. Just thought the knowledge base of the experts for such a program might run a little deeper. :cool:
Most of the 'experts' I talk to think the bullets tumble through the air like tomahawks.
Heavy Metal
05-20-11, 11:05
Superior performance is a contextual thing.
Superior in relation to penetration of light cover? 7.62 wins.
Superior in a ballistic context? I have seen evidence that a yawing and fragmenting 5.56 is more destructive to tissue than the 7.62 in it's M-80 ball loading. Doc GKR is the one to ask in that regard.
Nephrology
05-20-11, 11:07
Hey, it's better than the line my buddy gave me yesterday - ".223 is only good for shooting rabbits."
He also is trying to build a pistol that shoots .40 super out of a Glock 21 for home defense....yeah.....
Heavy Metal
05-20-11, 11:16
Hey, it's better than the line my buddy gave me yesterday - ".223 is only good for shooting rabbits."
You buddy obviously has never shot a Rabbit with a 223 then. Any kind of varmit round will shred one to giblets. It is way overkill for rabbits taken at less than 200M.
Most of the 'experts' I talk to think the bullets tumble through the air like tomahawks.
LOL. :help:
https://www.m4carbine.net/showthread.php?p=259798&posted=1
https://www.m4carbine.net/showthread.php?t=35029
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I remember hearing that if you shot someone running at you, in the shoulder the bullet was so unstable, it could come out their hip...and vice-versa, of course.
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I heard that 7.62 x 51 is more effective than .50BMG.... Ok, I didn't hear that yet but I should be hearing it soon since that's the way the logic is flowing nowadays.....
I heard that 7.62 x 51 is more effective than .50BMG.... Ok, I didn't hear that yet but I should be hearing it soon since that's the way the logic is flowing nowadays.....
Or, to follow the other "logic" to its conclusion, every Soldier should be carrying a single shot .50.....works both ways;)
Bob
Most of the 'experts' I talk to think the bullets tumble through the air like tomahawks.
This is how it was explained to me at the Ft. Sill range in 2003. I knew better than to discuss the matter at the time.
It was found that sometimes the new 5.56 round created a larger wound than the 7.62x51 when the 5.56 round struck with enough velocity that the bullet broke and fragmented when it destabilized. The problem was the bullet couldn't be counted on to always fragment
The 5.56 with expanding bullets are very devastating on jackrabbits and will blow a good sized hole, about fist sized to double fist sized, on exit. However, the terminal effects aren't enough to "shred" them. Can't tell you about cottontails, which are much smaller than jackrabbits, as we shot them for the pot and used 22 rimfires or shotguns. (Keep in mind my definition of "shredded". I've seen jacks torn to pieces when struck amidships by a 22-250.)
As far as FMJs go, I will not use them to hunt jackrabbits anymore, whether it's from the 5.56, 30-06 or 308. They tend to just poke a hole through a jack and don't put them down. I've shot a few jacks with FMJs and watched a small puff of fur pop from their chests and have had them take off. They don't run full speed, mind you,they hop off like someone kicked'em hard in the belly, but I kept having to chase them down and shoot them a couple more times. Strangely, I didn't have that trouble when shooting them with a 22 long rifle.
My dad & brother have cleanly taken deer, using the proper bullet in their 223s, shooting them over a feeder in Texas. So much for the 5.56 only being good for rabbits!
The difference in RPM between the 1:14 and 1:12 twist isn't enough to make a difference in the stability of a bullet travelling through the denser medium of a body.
It's been said a thousand times, but it bears repeating- If the US military were allowed to use the best of our bullet technology in battle, there would be no more question about the terminal effectiveness of either the 5.56 or the 7.62x51
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