7.62x39 v. 7.62x51 short range wounding differences

[481]

7.62x51 has longer range, flatter trajectory, more energy, and more accurate than 7.62x39. None of those things are my question.

My question is, at ranges less than 150 yards, how much difference would there be in wounding characteristics against human adversaries for these 2 cartridges?

Well, since you're looking for a way to quantify the difference in performance at range for the 7.62x51 M80 (147-grain FMJ @ 2,800 fps) and the 7.62x39 M67 (123-grain FMJ @ 2,329 fps) why not use what the US military has used for that same purpose since the early-1960s? The SLV (survivability, lethality, vulnerability) equations discussed and applied in this post are still in use by the US military today in the ballistic insult subroutines contained within ORCA/MUVES-S2 software that has been used to ''match'' the lethality of our small arms munitions to that of our adversaries over the last 50+ years with great success. To the credit of this long-proven modeling approach is the development and fielding of the 5.56NATO M193 which was developed (using these same models) to have the same lethality as the Soviet 7.62x39 M43 that allowed our troops to carry considerably more ammunition afield while still matching our adversaries' munition's capabilities.

The US military which tends to evaluate the lethality of such munitions in terms of probability of incapacitation— or P(I) —and still relies upon the P(I) model that was initially developed in 1968 by Sturdivan & Bruchey at the U.S. Army Ballistic Research Laboratory (BRL) at Aberdeen Proving Grounds, Edgewood Arsenal. The BRL P(I) model is still employed in the US Army's Ballistic Research Laboratory ORCA/MUVES-S2 SLV software and is still referenced in recent research pertaining to the development and evaluation of new munitions. Assuming stable, 'nose-forward' flight through a human torso and a G7 ballistic coefficient of 0.200 for the 7.62x51 M80 and a G7 ballistic coefficient of 0.155 for the Soviet 7.62x39 M67, the velocities can be computed for use in the BRL P(I) model which are presented along with the corresponding BRL P[I/H] at each range for each cartridge.



As can be seen from the probabilities above, using the US Army BRL model to evaluate the US 7.62x51 M80 and the Soviet 7.62x39 M67 at ranges less than 150 yards, the 7.62x51 is superior to the 7.62x39 at all ranges.

Finally, using the US Army BRL ΔE15 parameter—a projectile's kinetic energy expenditure from a penetration depth of 1 - 15 centimeters—it is also possible to determine the expected time to incapacitation (in seconds)— or T(I) — for each projectile at those respective ranges:



Once again, the 7.62x51 M80 produces shorter expected times to incapacitation than the 7.62x39 M67 at all listed ranges.

 

[mac66]

Having shot a good number of white tail deer with both the 7.62x39 and the 308 I have to say that the 308 is much better killer, at least on deer. I've had too many deer run away and have to be tracked with the X39. No tracking ever with the 308. That's with soft point hunting ammo in both calibers. I don't/won't hunt with the x39 anymore.

I've never shot an animal (or human) with FMJs.

And....I'm aware of the difference between the 7.62x51 nato and the 308 Win. FMJ nato loads are a different animal than the 180 gr SP hunting load.

 

[bfoosh006]

As per the OP...
"To phrase a little more clearly, if you knew that you would never have to shoot longer than 150 yds, is the ballistic superiority of the 7.62x51 over x39 worth the increased recoil, increased weight of the rifle, and higher price of the ammo?"

Probably not given that comment.

However, as mentioned the slightly faster incapacitation aspect could save your life. .... But , the follow up shot from the lower recoiling 7.62x39 "might" negate the previous comment when facing numerous adversaries.

I also think bullet design, against thin skinned targets, can help tilt the "answer" one way or another... quite a bit.

Lets face it... the perfect combat round still hasn't been made. ... even one intended for inside 150yds.

Some one mentioned the "will to fight" aspect, even after being shot ... look up some of the various Medal of Honor Recipents. That also should be considered.

 

[d2wing]

No doubt 7.62 NATO is superior to x39. That is not what I was asking. The question is, how much difference will it make at 100 or 150 yds. I was trying to be very specific with the question so the thread wouldnt go off on a tangent.

To phrase a little more clearly, if you knew that you would never have to shoot longer than 150 yds, is the ballistic superiority of the 7.62x51 over x39 worth the increased recoil, increased weight of the rifle, and higher price of the ammo?

The weight of the rifle can be whatever you want. But an AK isn't much if any lighter than a M-14 and an AR in 308 is likely lighter and better balanced. Recoil would be a difference depending on the weapon and situation. Mainly matters in full auto which is why the 7.62x39 was invented. In semi auto it's an issue but not much of one.

 

[Balrog]

The weight of the rifle can be whatever you want. But an AK isn't much if any lighter than a M-14 and an AR in 308 is likely lighter and better balanced. Recoil would be a difference depending on the weapon and situation. Mainly matters in full auto which is why the 7.62x39 was invented. In semi auto it's an issue but not much of one.

Ruger Mini thirty would be about 3 pounds lighter than a M1A.

 

[Bearcat1982]

What I'm saying is Ive never seen a guy take a 7.62 Nato COM and stay up except for a guy shot at 350 meters. Everyone closer, and longer too, has been down hard pretty much immediately.

I can't say the same about 5.56 or 7.62x39. I shot a guy at 50 yards with a modern defensive round 223 and it took two shots. First one was definitely fatal, but he was still in the fight for a short time after.

Im pretty sure this Gentleman answered the question handily.

 

[PWC]

.308 in any of it's variants is a 30-06 short in any of the same variants.

 

[BreechFace]

With the new 16" barreled Ruger SFAR in 308WIN coming in at 6lbs. 8oz. it really moves the needle on power to weight ratio.

 

[Shawn Dodson]

x51 has a greater chance for a hydrostatic shock (remote wounding of structures away from the wound channel) stop, but hydrostatic shock isn't a given.

What people believe is "hydrostatic shock" is the temporary cavity.

 

[Miami_JBT]

Yeah, no meaningful difference even out to 200 yards. If a whitetail, hog, or a two legged varmint is DRT after being hit with a good bullet in x39, it can't be any more incapacitated than dead. And 7.62x39 is not inherently inaccurate, or less accurate than 7.62x51. It depends on the brand and type of bullet used in both.

I shot my first ever sub MOA groups about two years ago with a CZ 527 in 7.62x39 using steel case Golden Tiger x39 made in Vympel Russia. The CZ likes that cartridge. Steel case Barnaul Silver Bear 125 gr JSP performed nearly as well. Silver Bear is good out to roughly 150 yards. The jacket separates a few inches after impact, but the core penetrates deep with a beautiful mushroom. Pretty decent for a bi-metal soft point projectile.

Vympel is the company, Amursk is thr city where Vympel makes the ammo in Russia.

 

[Beck]

Vympel is the company, Amursk is thr city where Vympel makes the ammo in Russia.

Yes, that is correct. The Vympel plant is in Amursk, and Amursk is in Russia. It's easier for me to cut to the chase and use the term "Vympel" when referring to the plant.

 

[Double Naught Spy]

What people believe is "hydrostatic shock" is the temporary cavity.

There is a lot of religion in general from what I can tell when I listen to people talk about terminal ballistics.

 

[Shawn Dodson]

There is a lot of religion in general from what I can tell when I listen to people talk about terminal ballistics.

Hydrostatic shock isn't a wounding mechanism. It's a layman's term without definition as to what it allegedly is and what it allegedly does.

Wounding mechanisms are:

• Penetration
• Yaw
• Fragmentation
• Permanent cavity
• Temporary cavity

 

[481]

The weight of the rifle can be whatever you want. But an AK isn't much if any lighter than a M-14 and an AR in 308 is likely lighter and better balanced. Recoil would be a difference depending on the weapon and situation. Mainly matters in full auto which is why the 7.62x39 was invented. In semi auto it's an issue but not much of one.

You're right.

Type-3 (milled) AK-47 (7.62x39): 8.7 pounds
AR10 (7.62x51): 8.9 pounds
M-14 (7.62x51): 9.2 pounds

The typical AK47 is about 8 ounces lighter than a M-14 and an AR-10 is just 3 or 4 ounces heavier than an AK47.

As you noted, not enough to be much of an issue.

 

[Double Naught Spy]

Hydrostatic shock isn't a wounding mechanism. It's a layman's term without definition as to what it allegedly is and what it allegedly does.

Wounding mechanisms are:

• Penetration
• Yaw
• Fragmentation
• Permanent cavity
• Temporary cavity

There are those that certainly do disagree.

Misuse and Modification of Fireworks With Fatal Injury : The American Journal of Forensic Medicine and Pathology

er upside down. The decedent then held the mortar base closely to his chest and lit the modified fuse. The resulting explosion caused severe blunt force trauma with significant hydrostatic shock damage to the heart and liver. This cause highlights the dangers of fireworks, particularly when...

journals.lww.com

http://journal-ene.gr/wp-content/uploads/2010/11/Tomos02_teyxos02-aggl.pdf#page=5

https://www.liebertpub.com/doi/abs/10.1089/neu.2013.3016

 

[BreechFace]

You're right.

Type-3 (milled) AK-47 (7.62x39): 8.7 pounds
AR10 (7.62x51): 8.9 pounds
M-14 (7.62x51): 9.2 pounds

The typical AK47 is about 8 ounces lighter than a M-14 and an AR-10 is just 3 or 4 ounces heavier than an AK47.

As you noted, not enough to be much of an issue.

Stamped AKM’s like the WBP Jack 7.62x39 hit the scales at just over 7lbs. Significant weight difference from AR10’s and M-14’s.

Interesting to choose a milled AK for the weight comparison which are by and large not the most common of AK’s.

 

[481]

Great.

 

[adcoch1]

You're right.

Type-3 (milled) AK-47 (7.62x39): 8.7 pounds
AR10 (7.62x51): 8.9 pounds
M-14 (7.62x51): 9.2 pounds

The typical AK47 is about 8 ounces lighter than a M-14 and an AR-10 is just 3 or 4 ounces heavier than an AK47.

As you noted, not enough to be much of an issue.

How much does a loaded m14 mag weigh vs an AK mag? There's the real difference.

I've used fal and cetme rifles for my main shtf weapon, and ak's as well. But I'd rather have more ammo for the same weight, so I no longer rely on a 308, and a lightweight 5.56 rifle is my go to. I like them all, I just don't have a need for 308 in a spray and pray weapon. So the intermediate cartridges work fine for me. But I like to load good bullets on top of the x39 case to hedge my bets...

 

[tactikel]

Dead is dead.

 

[Shawn Dodson]

There are those that certainly do disagree.

Misuse and Modification of Fireworks With Fatal Injury : The American Journal of Forensic Medicine and Pathology

er upside down. The decedent then held the mortar base closely to his chest and lit the modified fuse. The resulting explosion caused severe blunt force trauma with significant hydrostatic shock damage to the heart and liver. This cause highlights the dangers of fireworks, particularly when...

journals.lww.com

http://journal-ene.gr/wp-content/uploads/2010/11/Tomos02_teyxos02-aggl.pdf#page=5

https://www.liebertpub.com/doi/abs/10.1089/neu.2013.3016

The abstract (summary) describes internal blunt trauma injury and calls it "hydrostatic shock". The injury is identical to being kicked in the abdomen and the blunt trauma injuring the liver.

Find us a medically accepted definition of "hydrostatic shock".

 

[Bcwitt]

Enter body armor. In that situation, 762x51 is clearly superior. Most modern infantry have good body armor. A major game changer.

 

[Beck]

Enter body armor. In that situation, 762x51 is clearly superior. Most modern infantry have good body armor. A major game changer.

And just like that, this thread goes off the rails on a crazy train. So I think it's time to remind the members what the OP's question was.

Balrog said:
"My question is, at ranges less than 150 yards, how much difference would there be in wounding characteristics against human adversaries for these 2 cartridges?"

I looked everywhere in the OP's posts, and I couldn't find anything about infantry with body armor.

 

[Balrog]

yes the intent of my question would be that the adversary is not wearing body armor. They also do not have access to a Bradley fighting vehicle.

 

[Bcwitt]

And just like that, this thread goes off the rails on a crazy train. So I think it's time to remind the members what the OP's question was.

Balrog said:
"My question is, at ranges less than 150 yards, how much difference would there be in wounding characteristics against human adversaries for these 2 cartridges?"

I looked everywhere in the OP's posts, and I couldn't find anything about infantry with body armor.

How is that crazy? If you get In a gun fight without armor, YOU are crazy.

 

[Bcwitt]

Why don't you just shoot 2 poeple w each & find out?? Who but one intending to murder would ask such a thing?? For God's sake, why would you shoot anyone besides an enemy combatant @ 150 yds?? Good luck w your self defense case.