6.8 SPC vs 7.62NATO vs 5.56NATO

[Bill]

I made baseless accusations in my last post?

Let me explain somethin' here...

In 1896 the US Army switched from .45-70 to the less powerful .30-40 Krag.

Then in 1906- just ten years later- they switched from .30-40 Krag to .30-06(US Cal.30).

Then in 1957 the .30-06 was ditched in favor of 7.62 NATO, and purchases 1.4 million M-14 rifles.

THEN, just 10 years later the change from 7.62 NATO to 5.56 occured.

And now people are babbling about the 6.8 SPC round and the M468...

To me it makes no real difference wrt lethality. I can kill my target quite fine with any of those cartridges. So again......i'm looking for the 'other things' a round gives you.

I wrote you a list of seven items which should be considered in weighing/choosing/comparing any small arm cartridge(s). When viewed against those criteria- for the typical soldier- the 5.56x45mm cartridge is CLEARLY the best overall choice.

In your world you're doing me a 'favor' by "trading up" to 7.62mm.......but in effect you're cutting my ammo load by 20% while simultaneously saddling all the females in my unit with weapons they cannot properly employ, and also sticking the mech troops with rifles that a lot of guys will biitch about because "these new weapons are too long and are always getting hung up in our cramped vehicles."

The M-16/M-4 series and 5.56mm cartridges are the longest serving rifles in US Army history for a reason you know.

The M-14 is a fantastic weapon...but in a co-ed army, it's just too big and heavy, and 7.62mm just kicks too hard, and even if it didn't, i can carry 20% more ammo for the same weight for an M-16.

PS: US Snipers have been issued and have used hollowpoint ammunition since the mid 80s. It's designated M852, and uses the fantastic Sierra Matchking 168gr JHBT projectile. M852 is fully legal for combat use by (all) US troops. The reason that FMJ is used over JHP for the vast majority of troops is because FMJ is vastly superior wrt tactical penetration......which of course means that FMJ is CLEARLY superior for battlefield use than JHP.

[leib10]

Also, the FMJ projectile is more aerodynamic than the JHP, giving it a longer range.

[Bill]

Not true at all.

The 168gr sierra matchking JHPBT is UNMATCHED for accuracy among .30 caliber projectiles.

[leib10]

I meant that as a general statement. The Sierra Matchking is an exception to the rule.

[Bill]

I'm sure there are quite a few match grade JHPBTs floating around nowadays. I would reckon Hornady and Nosler and Speer et al all have their own version of a .30 cal JHPBT.

In pistols, your observation is quite correct. Not quite so with spitzer type rifle bullets.

[Gunny762]

I think it's irrelevant.

A lethal zone hit with any of the three WILL kill you.

A lethal zone hit with any of the three MAY put you down immediately, or it may put you down 30 seconds, or it may put you down in a minute or two.

So if they all do the same thing wrt APERS(anti-personnel) performance, then they should be judged on other merits.

Based on the merits of low recoil, large ammunition count, ease of training, required weapon size, and relative good accuracy the US and NATO have chosen the 5.56mm.

Based on those criteria it is a very sound selection.

7.62x51 and 6.8 are both better penetrators with better inherent accuracy potential and generally better downrange performance, but both cost the user in the categories the 5.56 excels at.

So IMO, you ask what it is that you want out of a round BESIDES just being lethal, and you go from there.

First off weapon size isn't true at all. An AR-10T A4 Carbine is only an inch or so longer than an AR-15 A4 Carbine, and weighs 1.5 lbs more, not a big issue, get stronger if its too much of a problem. HK91s and FALs aren't much heavier than a standard M16A2, and are actually smaller physically. Now that's put aside, I think you are focusing on ideals a little too much. I'm just going to assume you are actually a sniper so based on this, it's easy to get this way when you are concealed and in a firing position out of range of infantry weapons. You can take the time to line up your shot because, if you are doing your job right, you aren't receiving any return fire because you are unseen. You can stress shot placement, which is very important, especially to a sniper, but not really practical when the bullets are flying overhead and all hell breaks loose. At 100 yards a .17 HMR to the head or chest is lethal, and you can carry far more .17 HMR rounds than a 5.56, as well as control shots far better, but you can't justify a switch to .17 HMR because of this. The 7.62 NATO is still far superior to the 5.56, and the 6.8 SPC. For infantry use its ideal. You know damned well that the 7.62 NATO is far from phased out. M240 GPMG, M14s, and every Army or Marine Corp issued sniper rifle is chambered in this round, for a reason. I think the 6.8 SPC has a well-deserved role in Special Warfare as a good compromise of terminal ballistics and capacity, but the end ballistics of the 7.62 round are unequivocal. With a 7.62 NATO round the hydrostatic shock for a shot to the leg can rupture a femoral artery or other limb shots rupturing vital arteries. This can make a leg or shoulder shot a rapidly fatal one (with a bigger hole drilled through making it harder to stop bleeding), should the situation not allow you to get a good head or chest shot off. Hydrostatic shock is a reliable way to kill someone, FAST, it's why BIG calibers are used when facing dangerous game. I'm sure you could put down a bear with a 5.56 if given enough distance and enough rounds to shoot it with, but why bother when it only takes one .338 Win Mag? You carry less of the .338 than 5.56, but you used more trying to achieve the same goal? Also the 7.62s penetration through bricks, wood, trees, thick brush, and concrete is not matched by any 5.56, meaning there are fewer places for cover. I've got an AR, it's a great gun, perfectly reliable and easy to service and clean, so there isn't a gun issue here, its a caliber issue, which is why my AR is an AR10. I think a standard GI can be lethal at 500 yards and effective at 1000 using an ACOG or M145 optical sight and an AR10. The 5.56 is a varminting caliber (and not even the best out of them, look at the terminal ballistics of a hot loaded .22-250 or .243 winchester) initially designed to give prarie dogs a hell of a hard time because of its very high velocity and good accuracy and there's no denying this. It's killed a whole lot of people on the battlefield, but there have also been a whole lot of, albeit doomed people, who have been able to shoot back or set off a grenade before they died because they weren't lights out immediately. I think the 5.56 was introduced to let lily-livered wimps who can't handle the rather mild recoil of a 7.62 weapon be moderately effective on the battlefield. The 5.56 has served valiantly, but a mistake long realized during Vietnam is finally being addressed with the resurgence of use and interest in 7.62 weapons systems. The US has bought back or tried to buy back many of its retired M14s it gave to new EU nations like Lithuania as a good will gesture, and for the first time since the civil war, US armed forces have been flexible about letting troops buy weapons, like Springfield M1As or DSA FALs. Even experienced British troops have opted for their old L1A1s instead of using their L85s because of the simple fact that anything a 5.56 can do, the 7.62 can do better, and at longer ranges, with better accuracy and terminal ballistics. In this era of terrorists and suicide bombers, you don't want them to be down, you want them to be dead as fast as possible. You don't want them to be able to fire off those last shots or set off that bomb before they die. I can't say a whole lot for the 5.56, and I don't think any snipers really can. Perhaps in a counter-sniper role, its high velocity can account for something, though I'd personally rather have a .300 Win Mag, with all the velocity of a 5.56 and 3 times the energy delivered with 4 times the bullet weight. You clearly like the M-21; I do too, but I sure as hell wouldn't like it as much if it were chambered in 5.56, would you?

[cdbruster]

Both sides are correct.

We can't just throw Newtonian Physics out the window. Although the 5.56mm has a initial higher velocity than the 6.8 and 7.62mm cartridges, it is weakest in overall inertia. I compare the 6.8mm to that of .40 cal S&W. People complained about the stopping power of the 9mm and also complained of the capacity of the .45 ACP. The .40 S&W is where they found their happy medium. There should be no issue as to which round, 5.56 or 7.62, will put a person down faster. There is more enery transferred from a 7.62 bullet to the person than there is from a 5.56 bullet to a person. The 7.62 will win every time! Now lets look at what would cause people to carry an M-16 vice an M-14 in lieu of the previous. 1. Lighther Weapon 2. Ammunition is lighter and requires less space. 3. An M-16 will put someone down however not as effectively as an M-14 if the round impacts in the same fatal / near fatal location. 4. M-16 is cheaper. 5. I'm sure I'm missing a few points. It's a matter of efficiency of the cartridge and rifle. What is the smallest, lightest and cheapest rifle that we can manufacture that is still effective. Whether the 5.56 is effective is the question. In my opinion, yes it is effective but setting on the relative minimum extrema! We want the weight, and capacity of the M-16 with the performance of the M-14; what do we do? We create a happy medium, the 6.8mm.

[Johnekgun]

Which means that the servicemen and lawmen that according to the latest Guns and Ammo are causing such high demand for 7.62mm rifles that Armalite, Springfield Armory, and DS Arms are all having to expand to meet demand are having to put up with all that and changing midgame for: greater penetration and effectiveness. Not to mention apparently there are reports of them trying to buy M-14s back from Lithuania according to Guns and Ammo, in addition to the refurbishment of the 40,000 M-14s that survived the Clinton administration.

So in your book going to something that's easier to lug around and shoot is more noteworthy then people having to go back to something that's a bigger pain in the butt to use because of performance issues with the 5.56. Sure that makes a lot of sense. Talk about being asinine.

Plus before DSA came out with their shorter gas piston its not like there really were carbine 7.62NATO rifles to compete with the already developed M-4 which itself is about in the performance range of a PDW, which weights much less and as does its ammo. 10 inch barrels make for a lot of wasted powder. Of course, the M-4 has proved to usually be sufficient so why wouldn't they transfer over? Not to mention you forgot to mention that the 5.56 makes the penny pinchers much happier, and the rifles you mention after long periods of use are surprise, surprise wearing out.

The main reasons I've read for going back are two fold. First they're finding issues as a DSA engineer put it more or less with their rifles shooting the car, instead of the bad guy hiding behind the car. Second the present overstabilized and AP rounds have an anooying habit of just icepicking the guys, and even if the 7.62 did the same thing it would make a hole 1.88 times bigger, which means 188 rounds 5.56 ~ 100 rounds 7.62 in terms of making icepick holes. The 6.8 basically uses the same rifles the 5.56 does, is presently up in the air, even if it may not actually go anywhere, and apparently is comparable in terms of effectiveness with the 7.62.

It is true designers are always struggling to equip troops with the lightest most effective rifle. It is also true and ironic that presently in Iraq US forces are appreciating a concept that has been losing ground in the past few decades. We are finally fighting a war where the old 30-06 would have been at home. More engagements are being afforded at the 300 yard plus range. Troops are now requesting more 7.62 MM NATO caliber rifles. Most often the M-14 because thats whats in the inventory and presently deployable.
It is also true that rounds like the 6.8 MM round and others like the 458 Beowulf (probably spelled wrong)and the 9X39 MM Russian development are designed to shoot in modified standard rifles of the designers countries armed forces. The standard is and always will be to be at least lethal anything else is as they say "gravy". It will be interesting to see if these new developments will be adopted at all. It seems like a long shot ( excuse the pun please) because so much money is presently being poored into development and testing of 5.56X45 MM weapons to replace current weapons ( SCAR and Ultimax 100 programs come to mind quickly). Of course there is at least one progran being done by FN to introduce a 7.62 MM NATO version of the SCAR

[bonehead]

Retooling from the .556 to the 6.8 is no big deal and would be well worth the effort.

[gunnut]

It's always a struggle between range and numbers. On the one hand, we (infantrymen) want to carry as many rounds as possible, just in case of a good fire fight. On the other hand, if opportunity arises, we want to reach out and touch someone. 5.56 has the numbers, but less range. 7.62 has the range, but not the numbers. The army is trying to put some M-14s back in service to complement the numbers of the 5.56 with the range of 7.62.

The 6.8 and 6.5 are more like a compromise, a jack-of-all-trades round between the 5.56 and 7.62. It would be nice if they have the range of 7.62 but in greater numbers. But time will tell.

Most engagement distances are less than 300m. Most fires are not carefully aimed. In that case, 5.56 is more useful. It's just as nasty as a 7.62 but we can fire more, fire faster, and in a more controlled fashion.

Sniper has been in combat. I take his words seriously. Some may not conform to the theoreticals in the lab or at the range, but they are real. Theoreticals can never supplant actual experiences, only augment. If they conflict, I'm gonna take actual experiences on the battlefield over lab results, however counter-intuitive they may be.

[bonehead]

Sniper has been in combat. I take his words seriously. Some may not conform to the theoreticals in the lab or at the range, but they are real. Theoreticals can never supplant actual experiences, only augment. If they conflict, I'm gonna take actual experiences on the battlefield over lab results, however counter-intuitive they may be.

That is the crux of the debate. From day one to today the M16/.556 combo has been lacking in combat. (Voiced by servicemen who were issued this combination.) There have been some major improvements in both the rifle and the round, but with all the cost and developement time could have just as easily been spent on either a new round, new rifle, or both. There are three reasons the M16/.556 has been in service so long. 1)Politics. 2) politics. 3) Politics.

How many snipers choose the .556 over the other options available to them?

[Triple C]

How many snipers choose the .556 over the other options available to them?

What a sniper needs has no bearing on the line infantry. A successful sniper rifle requires a level range and accuracy unneeded in an assualt rifle and "stopping power" has as much to do with it as my foot.

Plenty of spotters have M16s.

First off weapon size isn't true at all. An AR-10T A4 Carbine is only an inch or so longer than an AR-15 A4 Carbine, and weighs 1.5 lbs more, not a big issue, get stronger if its too much of a problem.

It's not the gun dude. It's the ammo.

HK91s and FALs aren't much heavier than a standard M16A2, and are actually smaller physically. Now that's put aside, I think you are focusing on ideals a little too much.

If they are so handy, why hasn't any police or military use it in close combat when given the choice?

I'm just going to assume you are actually a sniper so based on this,

He is.

it's easy to get this way when you are concealed and in a firing position out of range of infantry weapons. You can take the time to line up your shot because, if you are doing your job right, you aren't receiving any return fire because you are unseen. You can stress shot placement, which is very important, especially to a sniper, but not really practical when the bullets are flying overhead and all hell breaks loose.

Then you have NO IDEA what is the standard rifle drill for close combat in the US Army. You have NO IDEA how bullets react to living men either. An off lethal zone shot will not kill, hence it will not reliably stop anyone. This is a fact for any rifle caliber. Even the disembowled or amputated could and did fight.

At 100 yards a .17 HMR to the head or chest is lethal, and you can carry far more .17 HMR rounds than a 5.56, as well as control shots far better, but you can't justify a switch to .17 HMR because of this.

At 100 yards a 9mm or smaller in a submachinegun had been considered adequate for the better part of the 20th century.

This can make a leg or shoulder shot a rapidly fatal one (with a bigger hole drilled through making it harder to stop bleeding), should the situation not allow you to get a good head or chest shot off.

Unless the bullet hits the brachial or femur there is no reason for anyone to bleed out from an extermity shot.

I think a standard GI can be lethal at 500 yards and effective at 1000 using an ACOG or M145 optical sight and an AR10.

An GI is already lethal at 500 meters with an M16 and 400 with an M4. At one kilometer no rifle is effective.

The 5.56 is a varminting caliber (and not even the best out of them, look at the terminal ballistics of a hot loaded .22-250 or .243 winchester) initially designed to give prarie dogs a hell of a hard time because of its very high velocity and good accuracy and there's no denying this.

WHAT?

I think the 5.56 was introduced to let lily-livered wimps who can't handle the rather mild recoil of a 7.62 weapon be moderately effective on the battlefield. The 5.56 has served valiantly, but a mistake long realized during Vietnam is finally being addressed with the resurgence of use and interest in 7.62 weapons systems.

Noticed how the Soviets dumped the 7.62 and went for the 5.54? And what 'resurgence' do you speak of, when virtually every military power worthy of the name switched to SCHV cartridges?

. . . for the first time since the civil war, US armed forces have been flexible about letting troops buy weapons, like Springfield M1As or DSA FALs.

Using none-standard firearm in the Army and Marines is a COURT MARTIAL offense.

Even experienced British troops have opted for their old L1A1s instead of using their L85s because of the simple fact that anything a 5.56 can do, the 7.62 can do better, and at longer ranges, with better accuracy and terminal ballistics.

Dare say, they're more exprienced then the CAR-15 totting paras, SAS and Royal Marines?

Just a thought: John Weeks, a WWII paratrooper and small arms expert, thought it positively a tragedy that assualt rifles weren't issued as the main battle weapon by WWII.

[pdf27]

Even experienced British troops have opted for their old L1A1s instead of using their L85s because of the simple fact that anything a 5.56 can do, the 7.62 can do better, and at longer ranges, with better accuracy and terminal ballistics.

Which troops would those be? All of the ones I've asked on the subject have been unanimous that 5.56mm NATO is MORE lethal than 7.62mm. All of them I've asked have experience on a two-way range (mainly in Iraq, but one guy had done a large number of other ops).
Incidentally, in my (admittedly rather short) time in the (British) army to date I have yet to even see an L1A1. So I think you're talking BS somehow...

[Johnekgun]

Schools of thought

I have been issued 3 different variants of the M-16. They all did exactly what our instructors said they would do. Men have died with first and second run M-16s in their laps. It was not the design of the weapon that failed them but the Army ordnance corps insistance on doing things its own way and using ball powder instead of the design team specified IMR powder. Those men died in the complex process of adopting an off the shelf weapon for issue to so many troops in the Army. It was the first time the primary infantry weapon would not be the design of Govt. armories. Its not hard to imagine the logistical nightmare this was back in the day. M-16s were issued without cleaning kits in many cases. What a mess. Things are different now... but are they better?

The Grendel and SPC round both seem to have very similar ballistic characteristics of the 7.62X39 round. This can't be an accident. The old Bloc round can really be destructive within its envelope so can the M-16 round. It cruises through cinder block with enough energy to kill after it passes through both sides. I"ve seen that happen. Its not the 7.62MM NATO though.This seems to be the same old argument I've heard and had with "old guys" over beers and shots forever. Bigger is better versus smaller and faster is better. We hear it in conversations relating to .45 and 9 MM comparisons. It is in the end apples and oranges. The Grunts that bring the fight to the enemy use what we give them.

[gunnut]

That is the crux of the debate. From day one to today the M16/.556 combo has been lacking in combat. (Voiced by servicemen who were issued this combination.) There have been some major improvements in both the rifle and the round, but with all the cost and developement time could have just as easily been spent on either a new round, new rifle, or both. There are three reasons the M16/.556 has been in service so long. 1)Politics. 2) politics. 3) Politics.

How many snipers choose the .556 over the other options available to them?

Actually the 7.62x51 NATO was the "new round."

US army realized the 30-06 was far too powerful for infantry work so they scaled down the round. Winchester had a 270 (or 240? can't remember) ready for the Army. But the brass wanted a 30 cal round, so they just trimmed the 30-06 and came up with the 308 Winchester, 7.62x51 NATO.

Incidentally, the .270 cal round just happened to be around 6.8mm