7.62x51: Two Marines’ Perspectives

7.62x51: two Marines Prsepctives

Lots of Monday morning quarter backing going on.
I don't want to be shot by either one.
A Trooper in Nam was shot in the hip area and the 5.56 ended up going out his shoulder, as he was sitting around cleaning his weapon, or the other way round. It's been a long time.
The bullet often does tumble when they get hit.
The hydroscopic shock does a lot of damage. A hit in the torso is going to put you down generally.
The 7.62 is bigger and just as fast at longer ranges. It does more damage further out.
The basic load was 900 rounds in 5.56. I don't remember what it was in 7.62.
But it is heavy very heavy. Ask anyone who humped a couple cans of belted ammo or a couple of belts or the machine gun.
The Mattel gun does great but at longer ranges and rougher targets the 7.62 wins, just as would the .50 Browning the projectiles being the same type.
I carried the m14 in basic and shot it on the flight line. It gave me a headache from the powder and recoil and flat steel recoil pad?
The Mattel gun I shot the first three hots at Ft Eustis into a nickle size group at 00 yards. Fire it all day with no fatigue and hit more consistently ater firing a lot of ammo.
 
someone correct me if i am wrong, but i believe the M-16 debuted with a 1-12 twist when it hit the scene. that twist could not stabilize the bullet causing it to tumble, and hence, resulted in devastating wound tracts. the M-16A1 "corrected" the twist problem, and lethality has suffered ever since. concerning the ability to carry more rounds, that may have contributed to the mentality that resulted in poorer round count to kill ratio ever since 5.56 became the standard issue (research "rounds per kill [name of war]" to locate stats). my research suggests that soldiers in WW2 were better marksmen, perhaps due to the fact that they knew every round mattered. perhaps if they carried 5.56 with the limited round count, the result may have been the same or close, since the limited number quite possibly may have resulted in making more accurate shots. just my 2 cents, but seems to fit.
 
I have read there is widespread use of drugs by the enemy in Iraq and Afghanistan-same thing was said about the Moros-that renders them much less susceptible to pain and hence harder to incapacitate. Biggest complaint I have heard about the 5.56 in the current conflicts is it lacks long range stopping power. There were similar complaints about the 30 Carbine in WWII and Korea.
I wonder how much of the problem is due to exhausted and groggy and sleep deprived GIs and Marines-who weren't such great shots to begin with.
 
I'd rather have this than any AR (and I do).

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someone correct me if i am wrong, but i believe the M-16 debuted with a 1-12 twist when it hit the scene. that twist could not stabilize the bullet causing it to tumble, and hence, resulted in devastating wound tracts. the M-16A1 "corrected" the twist problem, and lethality has suffered ever since.
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The M16 & A1 used the 1:12 twist, and the ammo was the 55 gr. M193. A 1:12 WILL stabilize that or lighter bullets, else you wouldn't be able to hit anything.

I've shot enough targets to 600 and beyond to know that combo is indeed accurate. In fact the I carried a M700 w/1:12 as a counter-sniper rifle and used M193 Ball in my duties. That rifle was extremely accurate.

The tumbling theory comes from the light high velocity bullet being easy to upset and does SOMETIMES start tumbling.

Thought the M193 is somewhat accurate, its light, it does not have a lot of energy or penetration at distance and is easier to be deflected by wind.

That is why the Army went to the 'A2, which has a 1:7 twist. It allows for heavier bullets which penetrate better and are less effected by wind.

I hope not to confuse anyone when I refer to heavier bullets needing a faster twist. Its not the weight of the bullet that determines twist requirements but the length of the bullet.
 
someone correct me if i am wrong, but i believe the M-16 debuted with a 1-12 twist when it hit the scene. that twist could not stabilize the bullet causing it to tumble, and hence, resulted in devastating wound tracts. the M-16A1 "corrected" the twist problem, and lethality has suffered ever since.
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You're wrong. That is a popular myth and has even been printed in books; but it confuses the difference between spin stabilizing a bullet in air and spin stabilizing a bullet in a much denser medium like a mammal, which is mostly liquid. It also shows a poor understanding of the bullet flight characteristics involved (which to be fair weren't even well understood until recently).

Suffice it to say, you'd need a twist like a machine screw to stabilize a .223 bullet in flesh, so 1:7 doesn't give up anything over 1:14. If you want the longer explanation, this PDF explains why the whole basic concept underlying that argument is wrong: http://www.dtic.mil/dtic/tr/fulltext/u2/a519801.pdf
 
kraigwy beat me to it!..;)

someone correct me if i am wrong, but i believe the M-16 debuted with a 1-12 twist when it hit the scene.
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You're right about that.

that twist could not stabilize the bullet causing it to tumble, and hence, resulted in devastating wound tracts. the M-16A1 "corrected" the twist problem, and lethality has suffered ever since.
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your NOT right about this.

The 55gr FMJ (M193 ball) was entirely adequately stabilized, and the M16A1 used the same 1-12 twist so no "correction" happened there (nor was one needed).

The tumbling so touted for the 5.56mm round in Viet Nam is an overblown myth with a kernel of truth buried inside.

The truth is that EVERY bullet longer than it is wide will yaw, (and eventually tumble if it has enough penetration) when traveling through a target medium.

The effect is most pronounced with Spitzer type bullets (the center of gravity is well toward the rear of the bullet) and the faster the bullet is moving, and the lighter it is affects the distance needed to travel though the target before tumbling.

The standard 150gr spitzer used in 7.62x51 NATO will tumble however, due to its size & speed, it usually doesn't show this tumble effect inside a body. In other words the bullet has (usually) passed through the enemy before it tumbles.

The small light faster .22 cal bullet tumbles sooner, often while within the body of the enemy. In other words, fewer inches of tissue deflect it more.

The part about the rifling twist rate causing the .22 bullet to be unstable and tumble in order to create greater wounds is complete BS.

As to "lethality" of rounds in war, based on kills vs rounds fired, it may be a useful thing when considering the entire mass of ammo used, but for comparing the performance of specific individual rounds against each other, its a red herring.

my research suggests that soldiers in WW2 were better marksmen, perhaps due to the fact that they knew every round mattered. perhaps if they carried 5.56 with the limited round count, the result may have been the same or close, since the limited number quite possibly may have resulted in making more accurate shots. just my 2 cents, but seems to fit.
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The number of kills/rounds fired would seem to suggest that, but you have to look at more than just those numbers to get anything other than a radically distorted picture.

Consider where those numbers come from, and how things differed in various wars. Some of these factors will also explain why just using the killed/shots fired data is insufficient.

WW I, .30-06, bolt action rifle 5rnd capacity.
WWII, same round, same rifles, plus the 8 shot semi auto M1 Garand
different tactics, with a big change about halfway through WWII.

You'll get different numbers kill/shots fired from both wars, using the SAME round. Why? One factor is the larger capacity of the semi making it easier to fire more rounds. ANOTHER factor is that pre WWII doctrine was that riflemen fired when they had a target, suppressive fire was the province of the machine guns.

About halfway through the war, combat experience and the veterans to teach it changed that. Riflemen were taught to put a round or two into anything that might conceal an enemy. That change right there is enough to radically skew analysis of both an individual rounds effectiveness and the troops marksmanship based on enemy killed /rounds fired.

Move up to more recent times with the M16 and you have 20rnd capacity, full auto, and light recoil, in the hands of every rifleman & other troopers. Its a rare GI who doesn't use full auto if its available. Simply put, GIs fired more ammo per kill in Viet Nam than WWII because they could. Move up to 30rnd sticks, and the same rifle, and that's a huge increase in rounds available to be fired, and so more will be used "per kill".

The guy with only one shot (at a time) tries hard to make it count. The guy with a full auto tries to make each burst count. Which one do you think uses more rounds per kill??
 
FWIW twist vs. stability: I have a 1:14 upper, specifically for coyotes. I regularly see one MOA with 55-grain flat-base soft-points.
 
You mean like a .222 Magnum? :)
Predates the .223, probably a better round but does not fit the AR.
14 twist was plenty for 55 gr flatbase spitzer or 52 gr boat tail.
 
I find it telling, people make excuses for the 5.56's effectiveness, while the most cited complaint of 7.62 is weight and capacity.
 
We are civilians. How many rifle gun fights are we going to get into? Even then, how many rounds are we going to shoot? I figure that a gun in 7.62x51mm is going to be more than enough. Now Magpul offers 25 round magazines!
 
I've found the opinions of military personal to be no more accurate than internet or gun shop chatter.
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That's a good statement. i spent a career in US Army EOD. Never shot anyone in combat. But i have killed a large number of wild hogs using the 5.56mm M193 rifle round. The effects of that bullet are devastating at ranges to about 150 yards when fired from a 20" or longer barrel: The bullet penetrates about 6", yaws and fragments. At lower velocities the magic is gone.

US Army Colonel and medical Dr. Martin Fackler, treated combat gunshot wounds. Dr. Fackler also conducted tests on military ammunition.

Wounds produced at velocities in excess of about 2,750 fps prove the M193 5.56mm bullet to be devastating. Conversely, the US Army 7.62mm M80 ball ammunition is not as effective. The German 7.62mm NATO ball round is much better.

http://kjg-munition.de/Zielwirkung/military_bullet_wound_patterns.html
 
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Bullet mass and bullet striking velocity establish a bullet's potential; they set the limit on the tissue disruption it can produce. Bullet shape and construction determine how much of this potential is actually used to disrupt tissue; they are the major determinants of bullet effect. Far and away the most disruptive bullet of those described is the West German 7.62 NATO round. Its fragmenting behaviour maximises utilisation of its much higher potential (bullet mass well over twice that of any of the 5.56mm bullets and velocity only about ten percent less than theirs) for tissue disruption.
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Military rifle bullet wound patterns by Martin L. Fackler
 
I just want to point put that US service rifles circa WWI through WWII were chambered for .30-06 but the rounds used have differences depending on their being .30 M1906, .30 M1, or .30 M2 ammunition.
 
When 'Spray-n-Pray' was the official doctrine (Vietnam) and the tall aperture sight was used so the M-16 so full-auto fire could be used, then the 5.56 made sense.

BUT, now days with excellent combat optics and the doctrine of aimed fire being prevalent (and more practice time given the grunts) then something close to the 7.62x51 makes sense.

I'm hoping a 6.5 to 7mm based on the AR being used. Doubt we will go all the way back to the 7.62x51 though.

Personally I've always wanted a FN-FAL Para 7.62x51!

Deaf
 
When 'Spray-n-Pray' was the official doctrine (Vietnam)
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I don't think that was the official doctrine. In reality, in a huge majority of firefights we didn't see who we were shooting at. SE Asia is jungle for the most part, you were shooting from one jungle patch to the next, that required "fire power", who produces the most fire power normally won the engagement. The difference is weight alone gave the M16a1 and its 5.56 (both light weight) a huge advantage.

We carried everything we had in the bush for months at a time, getting re-supplied about once a week. Weight as critical, every pound you could save met we could carry more ammo and just if not more important, canteens.

That's why I call BS, (as unrelated) when people discuss the "rounds expended vs. bandits hit", what wins firefights is "violence of actions" and that is more critical when you cant even she who you're shooting at.

Now as to this part:

and the tall aperture sight was used so the M-16 so full-auto fire could be used, then the 5.56 made sense.
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I have no idea where that came from. Don't quite what to say, except the tall front sight has no relationship to full auto fire. I believe it has more to do with the gas system being above the barrel but I don't know what was in Mr. Stoener's mind when he designed the rifle. However, I do know it works.
 
...even if you missed CM and only hit an extremity, the round had enough kinetic energy to literally take the person off of his feet.
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Any Physicists here that want to try and explain the law of, "...for every action there is an opposite and equal reaction..."? Doesn't that mean the shooter would be knocked down by all the "kinetic energy", also? Seems to me that a .308 bullet that pierced a human arm would not impart hardly any of the kinetic energy it possessed whereas the shooter would actually experience much more to his shoulder. Correct me if I am wrong. Besides, I thought that getting hit in the arm and being knocked down only applied to the .45 ACP. :D
 
and the tall aperture sight was used so the M-16 so full-auto fire could be used, then the 5.56 made sense.
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There are two possibilities with this statement. One is that it is referring to the two position aperture rear sight, the "tall" one being marked "L" for Long range (300M). If so, the rest of the statement makes little sense.

IF the statement refers to the sights being "tall" because they are on the carry handle (and tall front sight base to match) that was a design feature, necessary NOT because of the placement of the gas system (the AK's gas system is on top of the barrel as well), but because of the straight line stock used.

The straight line stock DOES aid in managing the recoil from full auto fire. But it is not a necessity to use a straight line stock to use full auto fire. When you do use a straight line stock, you must mount the sights high enough the shooter can get his eye behind them to use them. That's why the M16 has raised sights.
 
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