5.56 77 Grain HP, as effective a sniper round as 308. 7.62?! Your thoughts

[Mamluke]

5.56x45 77 Grain HP, fired from an AR platform rifle, heavy barrel 18~20 inch such as an MK-12. Can it be as effective as a dedicated .308 or 7.62x54 sniper rifle?

Pros:

Light weight, agility and mobility.
Full auto capability.
Can be deployed quickly and in All scenarios.
You run out of ammo, just borrow from the guy with the M4/AR15 ... :P


Cons:

Ultra Long range effectiveness.
Anything else?!

MK-12



An interesting video on the subject:




.... ....

[evidens83]

Let's just say I wouldn't want to get head- shotted with either one

[MrPlink]

Let's just say I wouldn't want to get head- shotted with either one

I make a much more general policy of trying to avoid being shot anywhere by anything PERIOD.

[goodlookin1]

From how far?

What kind of 77gr bullet? What kind of .308 bullet?

How fast?

What's the Ballistic Coefficient?


There are so many questions that need answering. But generally, outside of 150-200 yards, NO, a 77gr 5.56 is not going to be as effective as a .308. Now if you're taking into consideration weight, speed, recoil, round capacity, etc....then you have to ask what will the primary purpose of the weapon be. If it's recon or scouting, sniping, then no. No one in their right mind would rather have a 5.56 than a .308 for this use. But if you're humping it for miles, doing a normal mission not knowing what distance any engagement will be, then you have something to talk/think about.

But this always ends up being a pissing match. What it usually comes down to is...(wait for it)...SHOT PLACEMENT.

JMHO.

[SlickmisterN]

I think a better more fair comparison would be betwixt 6.5 Grendel, 6.8 SPC, and the .308 you mentioned. 5.56 and .308 were designed with completely differing goals.

[Mamluke]

From how far?

What kind of 77gr bullet? What kind of .308 bullet?

How fast?

What's the Ballistic Coefficient?


There are so many questions that need answering. But generally, outside of 150-200 yards, NO, a 77gr 5.56 is not going to be as effective as a .308. Now if you're taking into consideration weight, speed, recoil, round capacity, etc....then you have to ask what will the primary purpose of the weapon be. If it's recon or scouting, sniping, then no. No one in their right mind would rather have a 5.56 than a .308 for this use. But if you're humping it for miles, doing a normal mission not knowing what distance any engagement will be, then you have something to talk/think about.

But this always ends up being a pissing match. What it usually comes down to is...(wait for it)...SHOT PLACEMENT.

JMHO.

Interesting and very well put analysis... so .308 is the undisputed king?!
Can one argue then that an MK-12 in 308 would still be a better choice than heavier bolt action/psl type rifles:

7.62x51

[zfields]

I dunno, nothing says "Im going to ruin your F**k'in day" like a .30 cal bullet to me.

[Merc1138]

Interesting and very well put analysis... so .308 is the undisputed king?!
Can one argue then that an MK-12 in 308 would still be a better choice than heavier bolt action/psl type rifles:

7.62x51

It's not the undisputed king, but it's been around for quite a while, is a NATO standard(well, 7.62x51 is), has more energy than 5.56, longer effective range than 5.56, and so on. There are of course other rounds besides .308 and 7.62 nato that can do as good a job or better(I'm not talking about .50bmg either) with varying ballistics as well.

[Richard Erichsen]

5.56x45 77 Grain HP, fired from an AR platform rifle, heavy barrel 18~20 inch such as an MK-12. Can it be as effective as a dedicated .308 or 7.62x54 sniper rifle?

DMR rifle systems include 5.56x45 mm weapons, but dedicated sniper systems for the most part do not. Even 80 grain loads just don't have the terminal performance at ranges in excess of 600 meters, which tends to be where DMR rifles end and where sniper systems begin. At 1000 meters+ the more exotic calibers tend to be used.

Pros:

Light weight, agility and mobility.
Full auto capability.

Precision rifles for longer ranges generally require different compromises than weapons designed for full auto. In a platoon or squad, base of fire would be established by a different weapon.

Can be deployed quickly and in All scenarios.
You run out of ammo, just borrow from the guy with the M4/AR15 ... :P

A DMR equipped soldier firing deliberate, well aimed single fire will usually be the last weapon in the section to run dry. The benefit might be the ability for the riflemen in the squad to use the DMR's ammo rather than the other way around.

Cons:

Ultra Long range effectiveness.
Anything else?!

What is "ultra" long range? 1000 meters is bloody far as it is. If you want farther it won't likely be a .308 used for the role, but a .300 Win Mag, or the .338 Lapua or even the .50 cal if ranges demand 2000+ meters.

MK-12

If the desire was for converged DMR/LMG/SAW/AR caliber the debates rage about calibers that are either designed specifically to extend range and energy beyond 5.56x45 but fit within the constraints of the AR15 lower/OAL cartridge length limit, or alternative for throwing out the limitation and using a longer case mid way or as long as the 7.62x51 mm which has a certain appeal if you assume budgets for throwing out millions of perfectly good M16/M4 lowers.

There is still a solid role for the 7.62x51 mm which has the range and energy the 5.56x45 mm does not. A better bullet would improve upon the performance of the 7.62x51 mm, but there is already a substantial gap between the 5.56x45 mm Mk262 and the 7.62x51 mm M118LR.

R

[Mamluke]

I dunno, nothing says "Im going to ruin your F**k'in day" like a .30 cal bullet to me.

LOL ... :P to me too!!!!

It's not the undisputed king, but it's been around for quite a while, is a NATO standard(well, 7.62x51 is), has more energy than 5.56, longer effective range than 5.56, and so on. There are of course other rounds besides .308 and 7.62 nato that can do as good a job or better(I'm not talking about .50bmg either) with varying ballistics as well.

Roger that ...

The Turks use the 308 round on many of their standing army battle rifles, especially border patrols ...



...

[IrishPirate]

when you compare the rounds on some sort of graph, i'm sure there will be areas where they overlap, meaning that the ballistics are equal for an application (or at least produce the minimal ballistics required). However....the two will not be perfect shadows of each other and will occupy different areas of that graph meaning that one can do something or fulfill a need that the other can't.

so to answer your question....yes and no. at certain distances, taking certain things into consideration...the two will be equal. at other distances and with other factors to consider, one will be better than the other.

there's a reason why there's more than one caliber bullet...

[Mamluke]

A DMR equipped soldier firing deliberate, well aimed single fire will usually be the last weapon in the section to run dry. The benefit might be the ability for the riflemen in the squad to use the DMR's ammo rather than the other way around.

There is still a solid role for the 7.62x51 mm which has the range and energy the 5.56x45 mm does not. A better bullet would improve upon the performance of the 7.62x51 mm, but there is already a substantial gap between the 5.56x45 mm Mk262 and the 7.62x51 mm M118LR.

R

.

L BEEE DAM****



.... nough said ...

[Mamluke]

so to answer your question....yes and no. at certain distances, taking certain things into consideration...the two will be equal. at other distances and with other factors to consider, one will be better than the other.

there's a reason why there's more than one caliber bullet...

TRULY PROLIFIC! I can't agree more!!!!

.....

[GM4spd]

For over 300yds ---I prefer the bigger caliber,period,regardless of bullet weight. Pete

[goodlookin1]

Interesting and very well put analysis... so .308 is the undisputed king?!
Can one argue then that an MK-12 in 308 would still be a better choice than heavier bolt action/psl type rifles:

7.62x51

No, .308 is not the undisputed king. And I am certainly no professional analyst. But within 100m, personally, I'd rather have a 5.56 due to it's speed and hydrostatic shock effect (the faster, the more damaging), and the increased round capacity and decreased weight. But they're both extremely damaging. And to be perfectly honest, I'd rather be spitting 55 grainers within 100m than 77gr pills that are going much slower. For all practical purposes though, 100m is a very close engagement. It doesnt matter which one you're shooting.....anything that ANY of those rounds hit is going to cause much pain.

I had a revelation about the AR-15 when I first shot my newly built .308 AR. The .308 was fun, but it had a lot of detriments to it compared to the AR-15 when considering anything inside 150-200m. It was heavy. It was bulky. It had a smaller round capacity (well, not in CA), it's more expensive (matters for us civvies), etc. When you mix that crap up with the fact that the AR-15 causes the same or just about as much damage as a .308 (depending on distance from 0-200m), it just doesnt make sense to build a .308 for CQB operation (to me, anything inside 200m). Mind you, the .308 does have a TON more energy when it hits, but energy isnt always the biggest factor in lethality. I'd take speed over energy every time, until the speed goes under about 2600 FPS. Once it goes below that speed, energy takes over and becomes more and more important as speed decreases.

The semi vs bolt argument is an old one. Pretty much it's generally recognized that semi's will typically exhibit slightly decreased accuracy and slightly less speed, but are much faster at follow-up shots and have less recoil. Bolts are generally a tad more accurate and can get the pill moving a bit faster, but at the expense of speed and recoil. So pick your hardware depending on your needs/wants. But the answer to "which one is better", especially when SHTF, in my book is thus: "The one that's in your hands"


Oh and by the way: The first pic which is labeled 7.62 is actually a .223/5.56 . Look at the mag, look at the rounds on the ground....dead giveaway.