Not Again: .223 vs. 7.62 by 39

[Matt304]

....

 

[dscottw88]

Between 5.56 and 7.62x39? I'd go with the 5.56.

Between the mini-14 and the AK? I'd go with the AK.

For the record though, I prefer the 5.56 M193's fragmenting capabilities much more than any 7.62 hole punch.

 

[sarduy]

1. get whatever weapon closer to you.
2. Call 911 (if possible) and try to count them
3. Use the item pictured bellow and RUN! (if you are alone) while talking to the police remember 3-5 bad guys againt 1 is not good odds..

if you have members of the familly..oh well... stay and protect them with your life!

 

[collateral]

I have a bushmaster 'm4', a yugoslavian m70ab2, and a n interarms wz. 88.

regardless of caliber 'effectiveness' at various ranges (any of the three will put the hurt on somebody at the op's range), I would want whatever gun I was most comfortable with (which for me is the wz. 88).

really the caliber makes no difference. either will negate soft body armor (which the gang members probably won't have anyways) at front lawn distances, they will both punch through car doors,
go with what you know. your life may depend on it.

all this talk about wanting to land hits at >100 yards is unnecessary. the topic wasn't about modern combat, it was about a relatively short range gunfight. bangers are probably going to be shooting with pistols, and shotguns. if they are well equipped they may have smgs or carbines but in my city, I think it would be unlikely.

just my opinion. no offense intended.

 

[oldfatslob]

Quote:
" I was enlisted for 4 years, and an officer for 5 years. I was also involved in the TET Offensive at Hue/Phu Bai. I don't think my mouth got any bigger when I became an officer. You might not want to insult several members on here who also served."

Never disrespected any members who served, however you enlisted, therefore you knew what it was like to be a grunt, therefore, you are the exception. Don't get me wrong, I have met some good officers, but the ones who are snoddy, and get people killed, or even others I've met that bolstered on about their "combat experience" when they should have known the ones that did have "combat experience" didn't bolster about them, and the other ones that my father regretted pulling into the fox hole, and was then criticized for by his other enlisted men for doing so, and others that busted him down because he didn't do exactly like the officers told him to (but still got the job done and saved his and others lives), I call them big mouth. However, not all are like that, and I have the utmost respect for those who served, except the ones who needlessly get people killed.

Quote:
"Perhaps, but it is a fact that 5.56 has less wind drift than 7.62x39:"

Show me. Other than that chart, you listed no source or whether the shots were fired at exactly at the same time. There can be several different wind velocities downrange at any given moment. Besides that, you think I'm gonna believe some manufacturers research that are promoting their own product? How about some independent tests with no bias?
And pretend you are a wind, man-wind, with 100lb pushing strength, and there are 2 other lead filled men, one 50lb and the other 70lb. Which can you push farther?

Heavier bullets are less susceptible to the same force of wind pushing them as lighter bullets. Point being, at those distances up to 800 yards which everyone is claiming the .223 is "accurate" to better ask a sharpshooter. But you could always use normal ranges when you are comparing normal "non-sniping" shooting with the 7.62 vs .223 say 150-300 yards, and have 2 shooters shoot rifle each at the same time with equal skill, and see how much they have to lead into the wind to get on target. http://en.wikipedia.org/wiki/7.62x39mm And the rifle designed around the 7.62 was the SKS, and I find it more accurate than the AK. So have one of the shooter use it.

Besides that, why do you think the 45 acp was invented? The 38 was not adequate enough to put down a drugged determine foe, whereas the heavier bullet was.

So, as far as what "I" am going to have to kill anything larger than a coyote, it'll be the larger heavier bullet. But anyone else is welcome to pick what they want.

 

[Zak Smith]

Show me. Other than that chart, you listed no source or whether the shots were fired at exactly at the same time. There can be several different wind velocities downrange at any given moment. Besides that, you think I'm gonna believe some manufacturers research that are promoting their own product? How about some independent tests with no bias?
And pretend you are a wind, man-wind, with 100lb pushing strength, and there are 2 other lead filled men, one 50lb and the other 70lb. Which can you push farther?

Heavier bullets are less susceptible to the same force of wind pushing them as lighter bullets.

False. It is BC not mass which matters. Wind drift is a function of BC and velocity.

If you don't believe the chart, run any ballistics program with BC and muzzle velocity numbers for various 556 and 7.62x39 loads and see for yourself.

You can lead a horse to water...

 

[woodfiend]

I would always go for the 5.56. The round is much more accurate and has superior terminal ballistics. Many times people have been shot with the 7.62x39mm and have kept on fighting. The reason for this is because of the fact that it is an overly stabilized heavy round that will trundle through everything without fragmentation. Now, if the round happened to shoot through a wall and into a person, the 7.62x39mm would trump the 5.56 because of the stabilization and would not fragment. I would plan on not shooting at people through walls and so I would use the 5.56. It would be less of a hazard to bystanders and is a better round that offers a wider spectrum of loads. That's my two cents.

 

[Zak Smith]

The reason for this is because of the fact that it is an overly stabilized heavy round that will trundle through everything without fragmentation.

No amount of spin stabilization that a barrel can effect can stabilize a bullet once it enters a medium as dense as water or flesh.

 

[oldfatslob]

I was mainly referring to after 300 yards, as in "sniping", but if you look at those "computer generated charts" which I'm sure the promoters of the .223 made, you'll see that out to 300 yards the difference in the wind drift is negligible, maybe 2.5 inches, didn't feel like doing the math. My point is that out past 300 yards, the .223 is not that good of a long range rifle because of the wind drift. I'd rather us an appropriate round with a long range rifle for that. Look and read what I wrote, thoroughly. But both of those rounds could hit a target to 300 yards, the question is using either hollow or soft points, what I prefer, which one would do more damage?

texagun,

I forgot to ask you, what was your observation on the effectiveness of the .223 round during the tet battle you seen? Would you have preferred a larger caliber?

Those men, is who you need to ask, like my dad and texagun. Not some folks like us who've not been in that situation looking at a computer chart.

If I want to shoot a horse that won't drink water, which would be more effective and humane? A 30 caliber, or a glorified hyped up ultra magnum 22? If I want to shoot that horse past 300 yards, I'll get a different rifle that either of those two.

 

[1832]

I resolved this debate by getting an AR Upper in 7.62x39. I would feel comfortable have either caliber on my Lower in an emergency. I must say that I was surprised at how well the 7.62x39 performed in an AR platform. Even with the steel cased stuff, it compared favorably with my 5.56 groups out to 200 yds. When I put some Lapua premium ammo through that 20" free float barrel, it was really an eye opener.

 

[35 Whelen]

This arguement amazes me. It reminds me of the silly justifications people used to argue that the 9mm is more effective than the 45 ACP. Higher velocity, blah, blah, blah.....
I have never shot a human being with either of the cartridges in question, and I hope I never have to. I have however killed many head of game with rifles ranging from .22 caliber to .45 caliber. Post mortem examination of wound channels in dead deer, elk and hogs is fascinating to me. I collect and keep every bullet I can recover from game I kill.
I can tell you, that in my experience, I have found that given like constructed bullets, with similar sectional densities, at remotely similar impact velocities, the larger bullet does more damage every single time. Think about it: all things equal, a .30 caliber bullet starts out making a larger hole than a .22 caliber bullet. Add to that the fact that a .30 caliber bullet will weigh more than a .22 caliber bullet, and now you've added momentum which will increase the penetration.
Please don't tell me about the "explosive effects" of .22 caliber bullets. I've seen that first-hand and can attest to the fact that all this does is lessen penetration. the only time this effect is important is when you're shooting vessels full of liquid in an attempt to impress your friends.
Bigger bullet=bigger hole.

35W

 

[MTMilitiaman]

Some people should read more and type less...

 

[elmerfudd]

I'm with 35 Whelen on this. A bigger bullet with more momentum and kinetic energy has the potential to do more damage and since I'm a civilian with bench full of reloading gear, I see no reason to confine myself to second rate bullets designed to conform to some absurd protocol of war.

Yeah, I do have a bunch of surplus ammo and new production military type ammo, but that's for plinking. For use against live targets, I go with modern commercial hunting ammo or reloads.

 

[Zak Smith]

I was mainly referring to after 300 yards, as in "sniping", but if you look at those "computer generated charts" which I'm sure the promoters of the .223 made, you'll see that out to 300 yards the difference in the wind drift is negligible, maybe 2.5 inches, didn't feel like doing the math. My point is that out past 300 yards, the .223 is not that good of a long range rifle because of the wind drift.

It's just worse after 300 yards. Here's the same data extended to 800 yards

_Bullet_           _BC_ _MV_         0     100     200     300     400     500     600     700     800 | YARDS
7.62x39           0.289 2350 >    0.00    1.44    6.14   14.75   27.92   46.16   69.48   97.28  128.85 | wind (inches)
556               0.243 3250 >    0.00    1.10    4.68   11.26   21.54   36.38   56.71   83.14  115.31 | wind (inches)

Fact: 5.56 has less wind drift that 7.62x39.

5.56 is also not a particularly excellent long-range round, but 7.62x39 is worse.

 

[Candiru]

False. It is BC not mass which matters. Wind drift is a function of BC and velocity.

I can see how velocity directly influences wind drift: The faster a bullet gets to the target, the less time the wind has to act on it. What I don't understand is how the ballistic coefficient of a bullet makes any definitive statement about the bullet's susceptibility to wind drift. Published BCs are based on a bullet's reaction to drag along its path of motion when fired point-first. Wind drift is drag that acts in a direction perpendicular to the direction of motion; the amount of drag is determined by the BC of the bullet as measured from the side, and I don't know that this is guaranteed to be proportional to the BC as measured from the front. In fact, it seems like sectional density from the side would increase with caliber: SD is proportional to mass divided by area, and for a section of a cylinder with constant density, mass will increase proportional to the square of the radius, while area only increases linearly.

What confuses the entire issue is that velocity can never be separated from BC. Load a 6.5 Creedmoor round to identical weight and velocity as 7.62x39mm and at any distance where ballistics matter, it'll be going a lot faster. Could it be that wind drift is dominated by velocity, not BC?

 

[Zak Smith]

Going along the lines of your post, BC affects flight time because velocity is lost at a slower rate.

Could it be that wind drift is dominated by velocity, not BC?

No, it's pretty clear that BC is the most important factor in downrange wind drift:

* Sweep BC
_Bullet_           _BC_ _MV_         0     250     500     750    1000 | YARDS
A                 0.300 2700 >    0.00    2.88    6.70   11.52   16.45 | wind (moa)
B                 0.400 2700 >    0.00    2.09    4.65    7.83   11.52 | wind (moa)
C                 0.500 2700 >    0.00    1.64    3.56    5.85    8.54 | wind (moa)
D                 0.600 2700 >    0.00    1.34    2.88    4.65    6.70 | wind (moa)

* Sweep Velocity
E                 0.500 2500 >    0.00    1.83    3.98    6.55    9.49 | wind (moa)
F                 0.500 2700 >    0.00    1.64    3.56    5.85    8.54 | wind (moa)
G                 0.500 2900 >    0.00    1.48    3.20    5.25    7.68 | wind (moa)
H                 0.500 3100 >    0.00    1.34    2.90    4.74    6.94 | wind (moa)

A practical interpretation of this data is that increasing the BC from 0.50 to 0.60 (which can often be done by simply choosing a better bullet) decreases the wind drift @ 1000 yards more than increasing the muzzle velocity from 2700 to 3100 (which is a huge difference in MV-- you need a much bigger case).

Now obviously there is a tipping point where your high-BC load is going too slow, but, it's lower than many might think, and it's usually in a flight regime where the shooter wants a lot less drop (or really: drop rate) to help with MV S.D. and ranging error. Here are three possible 308 loads:

_Bullet_           _BC_ _MV_         0     250     500     750    1000 | YARDS
308 155           0.508 2900 >    0.00    1.45    3.14    5.14    7.52 | wind (moa)
308 240           0.71* 2200 >    0.00    1.51    3.24    5.21    7.40 | wind (moa)
308 240           0.71* 2000 >    0.00    1.75    3.75    5.98    8.35 | wind (moa)

308 155           0.508 2900 >   -0.00    2.32    8.81   17.44   28.75 | drop (moa)
308 240           0.71* 2200 >   -0.00    4.68   15.46   28.84   45.25 | drop (moa)
308 240           0.71* 2000 >   -0.00    5.93   19.24   35.76   55.95 | drop (moa)

308 155           0.508 2900 >    0.04   -0.08   -0.25   -0.49   -0.84 | drop per yard (inches)
308 240           0.71* 2200 >    0.06   -0.15   -0.41   -0.77   -1.23 | drop per yard (inches)
308 240           0.71* 2000 >    0.06   -0.18   -0.51   -0.95   -1.52 | drop per yard (inches)

-z

 

[Candiru]

How is wind drift measured? I would imagine that thousand-yard-wide wind tunnels are in short supply.

Also, what I meant by asking about velocity and wind drift pertained to an apples-to-apples comparison of two bullets of identical weight and muzzle velocity, but different ballistic coefficients. Given that all objects fall at the same speed, the reduced bullet drop at range seen for a bullet with high BC means that it's getting there sooner, which means that it's spending less time having force exerted on it by wind. The heavy, high-BC .308 bullets listed also seem to contribute as much proof to the theory that bullet mass acts against wind drift as they do to the BC theory.

 

[Zak Smith]

Go read McCoy's tome on external ballistics-- or at least the highlights about accuracy and how the original models were verified against reality. The modeling of symmetric projectiles' flight is so good that the Army basically shut down their research group on the subject, a few decades ago if I remember correctly.

The heavy, high-BC .308 bullets listed also seem to contribute as much proof to the theory that bullet mass acts against wind drift as they do to the BC theory.

Except the computer does not know about the mass-- only the BC. The point is, it's all rolled into the BC value. You can accurately model small-arms trajectory (ie, not artillery) knowing just the MV and BC (and environmental conditions).

 

[Candiru]

Just to make sure, the McCoy book you're talking about is "Modern Exterior Ballistics: The Launch and Flight Dynamics of Symmetric Projectiles" by R. L. McCoy, right? If so, I'll definitely pick up a copy. Does he talk about the mechanism by which BC influences wind drift?

 

[Zak Smith]

That's it. It's a bit expensive. I'm sure he covers that; it covers everything.

 

[subierex]

At 300 yds, gimme a scoped bolt-action in a heavier caliber than either of those two. As such, I would choose the AK in 7.62x39 with M.O.Badguy accuracy.

 

[TNThomas]

If i was being shot at by gang members, i would pick up my ak, because i dont have an mini 14. But i would rather use my Mossberg 590, 9 shells of 00 should do the trick at close range a little better. I would rather not be in that situation at all,

 

[Ignition Override]

How about bad guys in a car who stop and shoot from the relative safety of it, or step just outside it then plan to jump back in-has this been discussed?
A guy out west says that he is in danger of a local gangbanger who knows where he lives-outside a city.

Being kind of new to any gun topic, wouldn't a round larger than .223 have a better chance of going through a windshield or a car door? I've read somewhere about problems with .223s penetrating windshields, or at typical angles.

If you don't have an AK (or the mag is empty), how about an SKS instead of a Mini 14 or AR-15, if the SKS is fully loaded, and where kids can not find it/reach it?
An loaded SKS with a loaded Mosin Nagant as back-up might help.
By the way, a suspected gangbanger offered the seller of my SKS $300, over in Nashville, sight unseen-an unsolicited phone call.
There was no ad for it. The stranger overheard one of his (seller's ) employees chat about it somewhere. Maybe the stranger thought it was an AK?
As back-up for a rifle, have you guys seen a Saiga combat shotgun in action? My brother and I saw guys testing one in Evansville last week at an empty range. They are developing a patent for a modified, fully-automatic version: Alliance Armament. It was impressive.
Even the semi- Saiga 12 might have my vote.

 

[ziggy222]

its not always about how big a hole the bullet makes.my 1st two whitetails i shot were with a 30-06 with 165 and 180 grain slugs.i was'nt impressed.they ran over 50 yards,one 100yards.i tried 125 grain gamekings slug and wow,they dropped immediately.i had a 125 grain 30 caliber slug going 3200fps,200fps short of what a 257weatherby magnum does,a gun thats killed every known animal on the face of this earth with a 117 grain slug going 3400fps.it caused immediate shock and death.i leaves a small slice all the way through with little damage to meat.there is a magic killing force for most bullet weights going over 3000fps.thats why i get fast kills with smaller bullets.i do make sure to use bullets that stay together long enough to go deep.i now use a 22-250 with 60 grain nosler partitions cause the 50 grain bullets are only offered in varmint bullets that blow up too shallow at 22-250 speeds but they two work.all my kills are immediate even if i don't hit a good area.i've had them drop dead on the spot from a hit anywhere from a gut shot to a shoulder hit.my hunting buddy uses a ruger223 bolt with 55grain gamekings and makes easy kills.this is'nt the only way to acheive kills,its just the reason why the 223 is a better killer than 7.62x39.yes smaller bulls have more wind drift than heavier ones at the same speed,but they are'nt going the same speed.if you push a light bullet fast enough then you get a light flat shooting accurate low recoil bullet with very little wind drift that creates instant shock resulting in death.now some soldiers have had to shoot people multiple times with the new guns their using now when shooting far away targets.this is because they shortened the barrels and lost vital fps needed for shock.its like being stabbed with a hot ice poker several times,but only when its a far shot.they needed guns short enough to get in and out of trucks quickly while policing over there.an 7.62x39 might do better in that situation but in one of our fine rifles and not some spray and pray type gun like our enemies are using.if the 223 is'nt getting up to speed then its loosing its best advantage.

 

[MTMilitiaman]

I can see how velocity directly influences wind drift: The faster a bullet gets to the target, the less time the wind has to act on it. What I don't understand is how the ballistic coefficient of a bullet makes any definitive statement about the bullet's susceptibility to wind drift. Published BCs are based on a bullet's reaction to drag along its path of motion when fired point-first. Wind drift is drag that acts in a direction perpendicular to the direction of motion; the amount of drag is determined by the BC of the bullet as measured from the side, and I don't know that this is guaranteed to be proportional to the BC as measured from the front. In fact, it seems like sectional density from the side would increase with caliber: SD is proportional to mass divided by area, and for a section of a cylinder with constant density, mass will increase proportional to the square of the radius, while area only increases linearly.

The answer is really simple. You're hitting all around it, and I am sure given enough time, you'd eventually get it yourself.

It has to do with time of flight. The longer the bullet is in the air between two given points, the longer forces of wind resistance and gravity can act on the bullet. Gravity is pretty simple. It remains constant and its value is known. Wind resistance is harder to calculate. Barometric pressure and humidity, the density of the atmosphere as related to elevation, and other factors all contribute. Now you may think these factors are seperate from wind drift, but they are not.

A bullet with a high BC is going to resist drag better. It is therefore going to maintain velocity better, and slip through the air more efficiently. So its time of flight is going to be lower than a bullet that starts out at a similar velocity with a lower BC. Less time in the air means crosswind, like other forces, has less time to push on the bullet. Therefore, the bullet with the lower time of flight usually has less wind drift.

You can see that neither the 5.56 nor the 7.62x39 listed in the provided ballistics table has all that impressive of a BC. The BC on the 7.62x39's projectile has a slight edge, but it can't match the significant velocity advantage of the 5.56. Because the 5.56 has so much higher an initial starting velocity, it's time of flight is lower. This means gravity has less time to pull it to the earth, so it has less drop, and crosswind has less time to push it laterally off course, so it has less wind drift. And it is all related to BC and velocity. Mass counts more in terminal ballistics than in external ballistics.

The only effect mass has in external ballistics has to do with mass in relation to bore diameter. Bullets of similar construction in the same bore diameter tend to get longer as they get heavier. Longer bullets have higher BCs. Therefore, the aforementioned heavy for caliber .308 caliber projectiles you mentioned are favored not because of their mass so much as because mass in that diameter and construction gives them higher BCs, and consequently, lower time of flight downrange.

A 125 gr .310 caliber bullet is pretty light for its diameter, so the opposite is true of it, esp regarding its modest starting velocity--low BC + modest starting velocity = bad. The 7.62x39 has pretty good terminal ballistics but its external ballistics fail it miserably. This is fine because the cartridge was intended for intermediate ranges and power levels associated with assault rifles, and because the 5.56 is failed by its terminal ballistics more than its external ballistics, so it evens out pretty well in the end. Beyond 160 yards or so, the 5.56 is going to be below the velocity it can be relied upon the reliably fragment. And without fragmentation, the 5.56 loses most of its effectiveness relative to the 7.62x39 simple because while it may still tumble, the projectile isn't as long and therefore, it displaces less tissue when doing so.

This is why I am a firm believer that the effective range of the AK and the M16 isn't nearly as different as some would like to pretend. The AK retains the mass, energy, and momentum of the .357 Magnum at the muzzle, at 300+ yards, but suffers from poor external ballistics and only a moderate level of accuracy. The M16 has the accuracy and external ballistics to hit beyond 300 yards, but its chief wounding mechanism is dependent on velocity, which is lost with range. So in my experience, both rifles are best within 300 yards or so.