5.56 vs. 7.62x39

[RXM]

The MK262 MOD 1 by Black Hills looks like a pretty devastating round: http://www.shootingtimes.com/2012/03...-mod-1-review/

When the bullet strikes soft tissue, the heavier base comes around and causes the bullet to yaw, or tumble. The hollow nose cone breaks off and often the bullet fragments at the cannelure. This happens across a wide range of the velocity spectrum, which is why MK 262 Mod 1 proved effective in SBRs in addition to the longer-barreled SPRs. M855—or “Green Tip”—ammo was designed for battles with a body-armor-equipped army, hence the name “Penetrator.” On unarmored targets, it just zips through like it was designed to do. MK 262 was a better option for the enemy the military was fighting in Iraq and Afghanistan, though the round obviously does not penetrate as much as M855.

Read more: http://www.shootingtimes.com/2012/03...#ixzz25KANsxdQ

Cool round but VERY expensive; slightly more than $1/round

Source: http://www.ammunitiontogo.com/produc...acturers_id/66

[TonyF]

No offense to the OP but I find this topic even more tiresome than the accu-wedge thread.

It's all about "software", not "hardware".

Whichever caliber or platform you choose, becoming proficient with it is the key.

That does not mean that technology has not advanced to give the shooter more advantages.

Would you take a Kentucky Long Rifle into battle? Or a Henry Rifle? How about an '03 springfield?

Sure, skill is good, but the hardware is very, very important too.

A kentucky long rifle is one thing but in the hands of a skilled marksman, a manually operated repeater (lever or bolt) does not give up much to a semi-auto.

Technology has its advantages but possessing the ability to put those advantages to good use is what makes the difference.

I personally know one fellow who is so proficient with a bolt gun I wouldn't want to be anywhere inside his threat range no matter what weapon system I had. For the record, I'm not referring to this guys prowess with a precision rifle, I'm referring to his ability with a generic sporter.

[EvoRich]

Evo, not to jump on the bandwagon with Valorius but the 5.7 is an awesome round. What you hear from a lot of people is that they expect or believe the performance to be bad because it is a small round and us, being American, believe bigger is better. This is usually the case with pistol ammo, but you can't look at the 5.7x28mm as a pistol round. It is much more of the performance characteristics of a rifle round. This means when it hits a target, it doesn't kill through sheer force like a pistol round does. Instead, it creates a massive hydroshock cavity which will tear apart any "hard" organs nearby like the heart or the liver. I've heard it compared to a small bomb going off in your chest if that gives you a better idea.

Long story short: 5.7x28mm has been proven in a scientific study to have similar killing potential to a .45 JHP. However it maintains its energy over a longer distance and since the bullet has a rifle design, is much more accurate over distance.

Didn't mean to stand up on the soap box but the "poor performer" comment got under my skin. Lots of people out there bash the round without actually knowing its true capabilities.


As for having a rifle round. I agree with you that having a rifle with a rifle cartridge is better for most situations. As for the 5.56 or 7.62, I refer you to my prior comment on the matter. Unlike a lot of people on this board (not bashing anybody), I have seen the effects of a 5.56 in a combat environment. The times I have seen somebody hit with the round, they tend to stop in their tracks and are either dead or are incapable of continuing to fight. Talk about stopping power or size of the round or anything else that you want. You cannot convince me that a 7.62 is better than a 5.56. They both do what they are intended to do and they both do it equally well.

I never said it was a poor performer. I said "it is said....". I stated I don't have experience with it and know very little about it. I'm merely going off the opinions of people who have personally used it in real life. I trust them over scientific studies.

[Lycanthrope]

The MK262 MOD 1 by Black Hills looks like a pretty devastating round: http://www.shootingtimes.com/2012/03...-mod-1-review/





Cool round but VERY expensive; slightly more than $1/round

Source: http://www.ammunitiontogo.com/produc...acturers_id/66

I wager you could easily get the same results from readily available .223 match or hunting rounds.....at much less cost.

It's just a Sierra Match King. Switching to the 77gr Nosler Custom Competitions (that I'm so fond) of would cut cost more if you have access to a reloading setup. If you're worried about setback a Lee Factory Crimp Die would fix that with civilian rounds.

Lycannotamagicrecipethrope

[ungawa]

But if you look at all the recent offerings from serious people trying to increase the terminal effectiveness over a wider range of conditions with people wielding AR type rifles, every "solution" has not been another 5mm round. They are all closer to .30 cal again.

6.8 SPC
6.5 Grendel
.300 Black Out
etc etc etc

What do all of these rounds have in common? They are VERY similar to the 7.62x39mm in bullet weight and velocity.

There is something else they all have in common. All of them are far, far more devastating than an AK-47 round. Why is that?

[Lycanthrope]

There is something else they all have in common. All of them are far, far more devastating than an AK-47 round. Why is that?

...and they are all developed to solve a .mil issue of having a full jacket bullet not fragment due to loss of velocity at farther ranges.

Larger diameters (1) leave a bigger hole if they don't frag (2) fragment easier than smaller diameter projectiles given the same weight...or often...even at greater weights than the smaller and lighter diameter projectile.

Sectional density plays a role.

However.......the tables quickly turn if the larger diameter bullet is limited by speed. A good example would be comparing a 200gr 30-30 bullet (comparable caliber to the 7.62x39) to a 140gr bullet pushed out of a 7mm Magnum. The .284 bullet in that case is much more devastating.

Lycanofftoshootthe7STWthrope

[TonyF]

All of the "super-duper" cartridges do have one thing in common with the 30R over the 5.56 and that is increased recoil impulse.

I have fired a few full auto's in my day from .45ACP to a full auto M14.

I have not had the pleasure of shooting a 6.8, 6.5, whisper or blackout but by their interior ballistics they are all similar. The AK in 30R is only marginally controllable in full auto mode. I must believe the same holds true for the 6.8, 6.5, whisper and blackout.

Recoil impulse and "control-ability" in full auto fire is something that always seems to be missing in the "5.56 replacement caliber debate" which is a HUGE issue for any .mil organization to consider.

[ungawa]

...and they are all developed to solve a .mil issue of having a full jacket bullet not fragment due to loss of velocity at farther ranges.

All of them fragment, unlike any common 7.62x39 load at any range. Even the softpoints and hollowpoints from Europe and Russia do absolutely nothing.

[Valorius]

I wager you could easily get the same results from readily available .223 match or hunting rounds.....at much less cost

From the commentary i've read and the gel tests i've seen, most .223 JHP's don't come near the damage of Mk262. Because it's got so much mass it throws a whole lot of fragments when the round tears itself apart as it hits 90 degrees of yaw. In the ballistics test i posted above, they recovered dozens of fragments from a single mk262. When the temporary cavity is at it's widest, those fragments lance the surrounding tissue at super sonic speed. Then as the tissue collapses back in to fill the wound it detaches, and causes massively disproportionate damage.

That's how i've seen it described by the usual experts.

Of course that's not to say that you could not replicate the effect for way less money by handloading SMK's, or get still very good effects from other rounds that are a lot less money. It's just that Mk262 seems to be in a league of it's own in 5.56mm. It's not even close to the best barrier load though.

All of the "super-duper" cartridges do have one thing in common with the 30R over the 5.56 and that is increased recoil impulse.

I have fired a few full auto's in my day from .45ACP to a full auto M14.

I have not had the pleasure of shooting a 6.8, 6.5, whisper or blackout but by their interior ballistics they are all similar. The AK in 30R is only marginally controllable in full auto mode. I must believe the same holds true for the 6.8, 6.5, whisper and blackout.

Recoil impulse and "control-ability" in full auto fire is something that always seems to be missing in the "5.56 replacement caliber debate" which is a HUGE issue for any .mil organization to consider.

What you're talking about is exactly where the 5.7x28mm absolutely shines. I know i repeat myself, but a P90 has about 30% less recoil than a military M4 5.56mm carbine. This is also an inherent feature of the Five Seven pistol. Approx 30% less recoil than 9mm. You can lay down a LOT of aimed fire with either one of them.

[northernlights]

I couldn't care less about full-auto fire... too expensive, too wasteful, and too "registered."

After reading this thread, I was really leaning AR-15. My last trip to the gun store, I held both, and I really liked the AR this time (I had been liking the AK before). I held each gun for a while, and I definitely noticed the weight of the AK. Not saying I was collapsing under its weight, but it would definitely be worse to lug around than the AR. Also, the "facts" (if there are such things) seem to be that the 5.56 fragments, so it will hurt the enemy more, but the x39 will go through cover better.

However, I may end up going AK-47, even though I could put a red dot (faster acquisition) and light (big advantage; sneak up on a target and blind them) on an AR, for the following reasons:

1. It's cheaper. There are 3 AKs sitting at my favorite gun store right now for $549.

2. The ammo is cheaper, which means I could get more of it faster.

3. The gun is more rugged. I have no intention of letting my gun go to hell and never cleaning or oiling it, but oil bottles are small, and what happens with your AR when you run out of oil and you can't get into town to snatch a bottle of Pennzoil from the local Autozone?

4. The round will do more in general. Sure, the 5.56 may have nicer terminal ballistics and be more accurate at longer ranges, but the x39 seems to excel in everything else. It will blow apart cover, travel through brush like it isn't there, go through glass, probably it would take out a vehicle's engine block a lot better, and it will definitely still kill.

My only concerns are weight, ergonomics, and lower round count on your person, but I am leaning AK because I feel like the advantages I listed may outweigh the ability to shoot more comfortably, carry more bullets, and have a better sight picture and a light. Anyone, feel free to attempt to persuade me otherwise. Even I will be surprised to find out what gun I end up with.