For the sake of argument, 5.7x28 vs 5.56x45 for standard issue round


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MTMilitiaman
June 21, 2008, 03:27 PM
Just because I am feeling feisty I'll play devil's advocate and pose the following question:

Why would the same arguments applied in support of the 5.56 NATO not applying more so to the 5.7x28?

Weight: Ammunition for the 5.7x28 is lighter than ammunition for the 5.56x45, as are weapons chambered for the cartridge.

Controllability: The 5.7x28 produces less recoil, making it more accurate and controllable on automatic fire, as well as making it easier to train new recruits who have limited exposure to firearms before military service.

The 5.7x28 SS190 round is said to have an effective range of 200 meters, where, IIRC, it is rumored to still be able to penetrate the standard modern infantry helmet (Correct me if I am wrong here.). While there is no disputing that the 5.7mm is less effective than the 5.56mm, there is also no disputing that the 5.56mm was less effective than the round that preceded it, but was still adopted for the aforementioned reasons. Also, the common arguments used to support the 5.56 still apply to the 5.7;"I still wouldn't want to get shot by one," and "shot placement is still key."

Note that I am not taking this argument to a level of complete absurdity. I am not claiming the same arguments still apply to the .22 Long Rifle, for example. Both the 5.7x28 and the 5.56x45 are marginally effective intermediate rounds with debatable stopping power that nevertheless seems to get the job done with current tactics at commonly occurring ranges.

The military has already incorporated multiple shots center of mass into its training. There is no reason that same tactics--hammer pairs and failure drills, could not be employed with the 5.7x28mm. There is also no reason the 5.7mm couldn't keep the bad guy's heads down while they were being flanked, and the 5.56mm lacks so much in barrier penetration compared to other common military rounds that there isn't much of it to lose going with the smaller 5.7mm round.

Additionally, going with the 5.7x28 would allow logistics to be cleared up by allowing the adoption of a handgun and a longarm in the same cartridge, effectively eliminating the 9x19 from logistics. The military would just have the 5.7x28, with larger 7.62x51 and 12.7x99 machine guns providing support from machine guns and sniper rifles.

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Nolo
June 21, 2008, 03:33 PM
I've often looked at the 5.7x28mm round as a true military round, provided one uses it properly.
People look at the 5.7 and say "that'll never stop anyone". Well, without a headshot, they're right that one bullet will probably not be effective.
What about two? No?
Three?
Four?
Five?
I almost guarantee you that five 5.7x28mm FNs will stop a bad guy faster than one or two 5.56x45mms.
Why? It's been proven pretty much to certainty that multiple hits are the true stopper. Hence why 12 Gauge 00 Buck is so effective.
Now, is it worth it to fire five cartridges at every bad guy you come across? Maybe not. I think the 5.7mm cartridge weighs somewhere around half as much total as the 5.56 NATO, so it really doesn't look good to have a 5 5.7 shots equaling two 5.56 NATO rounds. The weight is disadvantageous. However, what if you could make the 5.7 lighter? What about more effective? What if you had a 5.7 FN that performed like M193? Wouldn't that be something worth considering?

Tyris
June 21, 2008, 03:35 PM
The 5.7x28 SS190 round is said to have an effective range of 200 meters,


Effective range on what? Coyotes?
The round has ballistics comparable to a 22magnum.

I think it is unfair to compare it to a 5.56, a more fair comparison in terms of muzzle energy is 9mm or 22mag.

-T

MTMilitiaman
June 21, 2008, 03:45 PM
Now, is it worth it to fire five cartridges at every bad guy you come across? Maybe not. I think the 5.7mm cartridge weighs somewhere around half as much total as the 5.56 NATO, so it really doesn't look good to have a 5 5.7 shots equaling two 5.56 NATO rounds. The weight is disadvantageous. However, what if you could make the 5.7 lighter? What about more effective? What if you had a 5.7 FN that performed like M193? Wouldn't that be something worth considering?

The same thing could and has been said concerning the 5.56 vs the 7.62 as well. When the 7.62 was the standard infantry round, people weren't trained in hammer pairs and failure drills. The 7.62 is also much better at defeating barriers and has a much longer effective range than the 5.56. But these advantages were deemed unnecessary given the distances most engagements take place. So is it worth it to use 2 to 4 5.56mm rounds for every 7.62mm round? The military thinks so...

Nolo
June 21, 2008, 03:53 PM
That's my point. As it stands, the 5.7 ain't much to look at. But stretch it a bit further...

mndfusion
June 21, 2008, 03:55 PM
I see ss190 as being more comparable to .17 hmr. I'd rather get a .17hmr pistol personnaly...

http://www.excelarms.com/acceleratorpistol.html


comparing ss190 with m855 and m193, is like compairing .308 and .223

Evil Monkey
June 21, 2008, 04:07 PM
the 5.7mm in comparison to the 5.56mm does not offer versatility. In Iraq, sure the engagement ranges I hear about are ranges from 50-100 meters. But what about in Afghanistan where 100-300 shoot outs are more likely? I don't think 5.7 is going to do the job very well.

Some forces across the world are realizing the forgotten utility of 7.62x39mm and in our military the SF were or are experimenting with 6.xx round, and you're arguing for a much weaker round? :scrutiny:

The better approach is with what's going on in the LSAT program. Taking the 5.56mm package and shrinking it without sacrificing performance.

SimpleIsGood229
June 21, 2008, 08:07 PM
I too agree that the 5.7 is simply not powerful enough. It's a pistol cartridge, really. Barrier penetration would really suffer, for sure.

Rubber_Duck
June 21, 2008, 08:23 PM
Go from 5.56x45 vs. 7.62x39mm -> 5.7x28 vs. 7.62x39? Doesn't sound very smart to me, IMO. I think our troops will STILL be facing the 7.62x39mm.

Nolo
June 21, 2008, 08:30 PM
Go from 5.56x45 vs. 7.62x39mm -> 5.7x28 vs. 7.62x39? Doesn't sound very smart to me, IMO.
That's not the equation. It's this:
Go from (1) 5.56x45 vs. (1) 7.62x39mm -> (>3) 5.7x28mm vs. (1) 7.62x39.
If you are using 5.7x28mm, you ain't gonna be using a little 30-round mag or 650 RPM anymore.
You'll be using a 100-round mag* and probably over 1000 RPM.

*2 50-round P90 mags weigh the same as 1 30-round M16 mag.

Deer Hunter
June 21, 2008, 08:32 PM
The 5.7x28 was not needed... There was already the 7.62 Tok, but I guess FN wanted its own round.

Oooo how I love to stir the pot.

Nolo
June 21, 2008, 08:42 PM
There's one advantage the 5.7 has over 7.62 Tok (which I, too love, DH): The base. 5.7 FN has an 8.0mm* base (I believe), whereas 7.62 Tok has a base just shy of 10mm. More rounds in the mag for 5.7 FN, which is rather important in the kind of weapon both of those rounds are suited for.
But you put expanding bullets in the Tok and the 5.7's game is over. O.V.E.R.
*It's actually 7.95mm. Case head is actually slightly rebated. :barf:

Z-Michigan
June 21, 2008, 09:48 PM
The 5.7 FN has a very, very small place in certain pistols and SMGs for police or non-infantry units, issued with AP ammo. Anywhere else I see no point for it.

For replacing the 5.56x45, well you'd be doing a major downgrade from a round that is already marginal. A 5.7 weapon is not usable as a rifle for infantry. It can replace an SMG in those type roles, but not a rifle, and definitely not a belt-fed MG. I see no reason for it.

IMHO, the ideal solution is something like 6.8 SPC or 6.5 Grendel, or even a 6mm-45mm hybrid. .243 Win or 6mm Rem would also be good, but perhaps too big and powerful.

Soybomb
June 21, 2008, 09:53 PM
5.56 gets a lot of heat for not being enough bullet for the job. 5.7 does a significantly lower amount of damage to tissue than 5.56, so much so that it doesn't hold up to the 7.62 > 5.56 comparison. 7.62 and 5.56 are both rifle rounds and both produce centerfire rifle style wounds, 5.7 crushes less tissue than a 9mm fmj round.

elmerfudd
June 21, 2008, 10:00 PM
If you are using 5.7x28mm, you ain't gonna be using a little 30-round mag or 650 RPM anymore.
You'll be using a 100-round mag* and probably over 1000 RPM.


That I could go with, but it's an entirely different school of thought. More like every soldier a machinegunner than every soldier a rifleman. I think that with training it could work, so long as the soldiers were delivering aimed machinegun bursts rather than using spray and pray tactics.

rbernie
June 21, 2008, 10:03 PM
You can't legitimately compare 5.7x28 against buckshot; all nine (9) 00 buck pellets in a 2 3/4" 12ga round are unleased at once on a single trajectory whereas you'd have to contend with muzzle rise and convergence time with a 5.7x28 in FA.

And franky, 00 Buck isn't used much past 50yds for a reason. Even allowing for better ballistics due to projectile shape, you just don't have and retain enough energy in the 5.7x28 to be effective at distance when dealing with combatants who are making effective use of cover.

Nope; 5.7x28 is a short-range round that does not really compete with 5.56NATO in most any way.

Onmilo
June 22, 2008, 12:05 AM
There is an advantage to the 5.7 as a combat round.
It is accurate enough and controllable enough to make head shots at reasonable ranges and contrary to popular belief, it is powerful enough to inflict lethal wounds without bursting the combatants cranial cavity like a ripe melon.

Too bad the weapons available are not living up to the accuracy potential of the cartridge.

GunTech
June 22, 2008, 12:13 AM
I've owned a FiveseveN and have put many 5.7x28 rounds into living creatures. The 22 hornet makes it look like a pipsqueak. I had to dispatch a large rabbit that took three rounds into the body from about 25 yards and was still trying to crawl away.

It may have a slight edge over a 22WMR. May.

I was so disgusted with the lack of performance of the round, particularly given the cost of weapon and ammo, that I will never buy another.

YMMV

Evil Monkey
June 22, 2008, 12:19 AM
That I could go with, but it's an entirely different school of thought. More like every soldier a machinegunner than every soldier a rifleman. I think that with training it could work, so long as the soldiers were delivering aimed machinegun bursts rather than using spray and pray tactics.

THAT'S WHAT 5.56MM and 5.45MM ASSAULT RIFLES ARE FOR!

The whole point to 5.56mm was to allow soldiers to carry more ammo and shoot controllable bursts. If you really want to have a "every body a machine gunner" philosophy then the least that could be done is to teach soldiers to use bursts on the M4/M16 and give them 45rd mags. Many militaries have been teaching soldiers to utilize burst fire for decades.

The most that could be done is equipping every rifleman with an AK108 5.56mm and 60rd quad stack mags. That's true 2nd generation assault rifle doctrine in full effect.

And the whole idea of using a smaller and weaker round for whatever advantages is plain old obsolete thinking. The goal today is to shrink existing intermediate or full power rounds into compact packages like telescopic cased ammo or caseless.

I win this thread. :D

elmerfudd
June 22, 2008, 01:33 AM
No, 5.56 and 5.45 assault rifles don't have 100+ round mags and cyclic rates over 1000 rpm. You can't lay down the same kind of sustained fire with them as you can with a standard machinegun. If you could they would be too much of an encumbrance for the average soldier. With a 5.7 it just might be possible however.

MTMilitiaman
June 22, 2008, 02:18 AM
THAT'S WHAT 5.56MM and 5.45MM ASSAULT RIFLES ARE FOR!

The whole point to 5.56mm was to allow soldiers to carry more ammo and shoot controllable bursts. If you really want to have a "every body a machine gunner" philosophy then the least that could be done is to teach soldiers to use bursts on the M4/M16 and give them 45rd mags. Many militaries have been teaching soldiers to utilize burst fire for decades.

In theory.

But since the military adopted the 5.56 under that philosophy, the average soldier has been denied automatic fire capability. The M16 is limited to three-round burst, and that capability is rarely used. And by rarely, I mean rarely--as is, almost never. The riflemen are trained to engage specific target with aimed fire, which IMO is a job more suited to the M14 that the M16 was intended to replace.

The only time I was ever ordered to set my M16A4 to burst was on range exercises where we were all issued enough ammo to just want to get done and go sit down again. Then we were pretty much instructed to dump ammo without regard to accuracy so we could "unload show clear" and leave the firing line. Automatic fire is almost solely to responsibility of the SAW gunner, which I also have experience as.

I've seen a training video claiming that the average engagement distance in current urban combat is 60 meters. I was told "under 100 yards." An aimed 3 to 5 round burst from a P90 is more than capable of this.

A very strong case could be made that whatever the typical 5.7 lacks in accuracy or long range stopping power, it makes up for in controllability. When the P90 came out, I read an article that claimed less recoil and muzzle climb than an MP5 with a flatter trajectory and better downrange performance. A 4 to 6 round burst could be deliver with enough accuracy at 50 yards to assure multiple hits.

The philosophy behind the 5.7x28 is very similar to that originally intended for the 5.56x45.

The whole point of this exercise is so that those who feel the 5.56 is the end all, be all, infantry cartridge can feel how those of us who supported the 7.62x51, or better yet, an intermediate powered cartridge between 6.5 and 7mm, feel. The arguments are the same.

Shot placement, controllability, and the weight of the ammo will never be the only factors to be considered.

Few of us support the 7.62x51, or larger, as the standard issue cartridge. Most of us, esp those of us who have humped with modern body armor and issued gear, understand the importance of weight. Most would support a standard issue cartridge between the 5.56 and the 7.62x51mm NATO cartridges, however, and despite modern training in infantry tactics, many still feel the 5.56 is too large a step in the right direction from the 7.62. A happy medium should and eventually must be struck...

PTK
June 22, 2008, 02:25 AM
*2 50-round P90 mags weigh the same as 1 30-round M16 mag.

Funny, mine sure don't when loaded. The P90 magazines are heavier by far.

Eric F
June 22, 2008, 02:33 AM
Why do people try to make the 5.7 something its not? It was designed to be a short range armor defeating round. And that is what it is good for. It is not a man stoper it was not intended to be a full on infantry round it is not designed to be a varmmit round. Just stop pretending and go with what it was suposed to be. I will never understand why people think it is some sort of mirical round the ballistics on it suck and in anything less than a subgun it wont be all that great for much else.

PTK
June 22, 2008, 02:38 AM
My PS90 (sbr) is for HD. If 50+ well placed low-flash low-noise rounds don't get it done, well.... I have an AR-15 ready too. :D

I carry a 5.7 USG. I fully realize that it's a tradeoff of "power" for a lighter handier gun with higher capacity. I don't make it anything it isn't - we're talking between a .22mag and .22 hornet for power levels, something I am perfectly willing to carry - and I do.

Link to gel tests (http://brassfetcher.com/SS195%20FMJ%20and%20SS197%20ballistic%20tip%20(bare%20and%20heavy%20clothing).html)

Matt304
June 22, 2008, 02:54 AM
The 5.7mm was designed as a close combat round.

Your argument is in persuasion of using a close combat round in a medium range scenario. This does not work out so well for the military. Better use for a SWAT team.

Just because you can hold and fire more of them doesn't mean you will be getting the same amount of usefulness. When it comes up against thicker armor, the 5.7 is at a great disadvantage.

MTMilitiaman
June 22, 2008, 03:05 AM
And many of us will never understand why people try to make the 5.56 into something it isn't.

It's a great varmint round. It works well on coyotes. But if the military can rate it as a combat round out to 500 yards and put 800 round BDC on our optics, then the 5.7 really is a comparatively 200 yard round.

Expecting what the military does from the 5.56mm isn't much more of a stretch than expecting the 5.7 to perform in modern sub-100 meter urban combat. Even the 9x19mm MP5 was rated for 80 yards. That's 20 yards more than the reported average engagement distance in Iraq...

Eric F
June 22, 2008, 07:06 AM
MTMilitiaman the 5.56 was designed to be a 500m combat round. that is what it was built for.

FN when the 5.7 was new made it plain in many articles that it is a close in armor defeating round.

Tomac
June 22, 2008, 08:51 AM
I'm a big fan of the 5.7 for HD/SD use but even I wouldn't suggest it for front-line std issue use. To correct an earlier poster, 5.7 ammo weighs half as much as 5.56 ammo, a fully loaded P90/PS90 50rd mag weighs about the same as a fully loaded 5.56 30rd mag.
Tomac

fearless leader
June 22, 2008, 09:26 AM
I agree with DEER HUNTER.
The 7.62x25mm Tokarev has it all over the FN round in performance.

I wonder how it stacks up to the 30 carbine?

It doesn't matter. Barack Obama will probably outfit our military with paintball guns.

MTMilitiaman
June 22, 2008, 09:58 AM
MTMilitiaman the 5.56 was designed to be a 500m combat round. that is what it was built for.

Perhaps. But how well it fills that role is debatable. I feel that is more than just a little optimistic.

The military could design a car around a 4-cylinder engine and call it a drag racer, but that doesn't mean it is particularly well suited to the task, despite the designer's intentions...

Evil Monkey
June 22, 2008, 10:04 AM
That's 20 yards more than the reported average engagement distance in Iraq...

Are you trying to say that since the reality in one theater of warfare tends to support your theory of a 5.7mm infantry weapon, that suddenly it should be accepted? Non sense. And what about other methods of warfare? Environments a soldier will fight through? The 5.7mm would never come close to achieving the versatility the 5.56x45mm, 5.45x39mm, 7.62x39mm, 5.8x42mm, 6.5x39mm, and 6.8x43mm.

And even if a 5.7mm, 100rd capacity, 1,000rpm weapon was to be adopted as general issue, the squad would STILL require a base of fire MG. There must be something that will pepper long range targets with authority and have the capability to chew through hard targets. If you still need a MG in the squad, then it looks like the full auto 5.7mm doctrine isn't working as planned. You're only trading range/power for more ammo and lighter weight and there's a limit to how far you can go with that and retain battlefield utility.

TAB
June 22, 2008, 10:06 AM
if the 5.7 was a great combat round, wouldn't all of the worlds armys be beating down FNs door for it?

elmerfudd
June 22, 2008, 10:43 AM
I don't think that anyone is fielding a great combat round at this point in time. The 7.62x39 probably comes closest, but it's got a rainbow like trajectory and tends to just punch 30 caliber holes. The 5.56 is pretty good when it fragments, but it's lacking in penetration and just makes a .22 caliber hole when it doesn't fragment. The 5.45 is just a 5.56 that tumbles better but doesn't fragment. The 7.62x51 and 7.62x54R have great ballistics and stopping power, but they also weigh too much and recoil too much.

What is needed is a midpower round like the 6.8 that both tumbles quickly and fragments nearly every time.

Eric F
June 22, 2008, 12:06 PM
if the 5.7 was a great combat round, wouldn't all of the worlds armys be beating down FNs door for it?

DING DING DING
Give that member a cigar!:D

Funderb
June 22, 2008, 12:15 PM
why not 5.7x35?
nice round in between! bigger diameter, and still fun!


haha I love throwing monkey wrenches in glass rooms.

Gunnerpalace
June 22, 2008, 12:18 PM
if the 5.7 was a great combat round, wouldn't all of the worlds armys be beating down FNs door for it?

Secret Service uses it, so if must not be THAT wimpy.

And if a 5 . 7 is a glorified .22 so is a 5 .56.

TAB
June 22, 2008, 12:26 PM
yes but the Secert service is not the miltary, they have a niche they wanted filled, the P90 filled that niche... Something you can conceal, high capicty, short ranged, not much in the way of penatration, low recoil, can defeat body armor with the right ammo... etc

Sounds like a great weapon to protect some one in a tight spaces. I bet they still use thier mp5.

Does not mean its a great combat round.

Gunnerpalace
June 22, 2008, 01:00 PM
Does not mean its a great combat round

That's true.

TexasRifleman
June 22, 2008, 01:01 PM
Does not mean its a great combat round
.....
That's true.

Doesn't mean it's NOT a great combat round either.

It has it's place; a submachinegun round when a high number of rounds on target in a very short timeframe is called for, with the chance that the hostile is wearing armor.

In that usage there probably isn't a better round out there to meet those requirements.

I don't think anyone is dumb enough to think that it's some kind of Battle Rifle round.

GunTech
June 22, 2008, 01:16 PM
The 5.7mm was designed as a close combat round.

No, the 5.7 was designed as a pistol replacement for troops that don;t have combat MOS. It was not designed for close combat. It was designed to replace 9mm ball from a handgun.

GunTech
June 22, 2008, 01:24 PM
MTMilitiaman the 5.56 was designed to be a 500m combat round. that is what it was built for.

Actually, the 5.56x45 was really meant as a 300 yard round. The designed was heavily influenced by the Hall study, which was itself influenced by the Hitchman report which noted that 90% of all infantry small arms fire including machineguns occurred at 300 yards or less, and that virtually all fire occurred at 500 yards or less for reasons that has more to do with the realities of combat than the capability of the weapon.

However, the Army has continually been pushing the requirements for the 5.56x45 to longer and longer range, while the reality is that bullet fragmentation is virtually non-existant past about 150 yards, and it is this behavior that makes the 5.56x45 disproportionately lethal for it's size. In Vietnam the 5.56x45 was actually shown to be 11% more lethal than the 7.62x51 - exactly because most combat operations were meeting engagements and ambushes at relatively short range.

Now with the popularity of the M4, velocities are reduced and the fragmentation range of the M855 is closer to 100 yards, beyond which the 5.56 behaves like any other ball projectile.

GunTech
June 22, 2008, 01:38 PM
What is needed is a midpower round like the 6.8 that both tumbles quickly and fragments nearly every time.

The 6.8 is limited in that it is restricted by the M16 magazine. Bullets are short, and therefor BC is poor. Fragmenting rounds seem like a great idea, but the problem is that then penetration suffers.

No matter what you do, you are going to have to compromise. You'll never get something for nothing.

As has been discussed in the 'ultimate combat round' thread, if you split the difference between 7.62x51 and 5.56x45 you end up with a 6.5mm 108 gn bullet at about 2850 fps. This is very doable although an ideal case will probably not fit in the M16 platform. The 6.5 Grendel comes close, but requires a 24 inch barrel to achieve close to the required velocities and the case shape is probably not ideal for automatic and particularly belt fed weapons

If you free the cartridge from the constraints of the M16 platform, the required performance can be has in a cartridge with moderate shoulder, good case taper and decent size and weigh. Given the excellent BC values of the 6.5, you can actually better the long range performamce of both the M80 ball and M118LR special ball but this requires heavier bullets with higher recoil. These bullets will also have very high sectional density compared to 5.56 and even 7.62 and so should have good performance against barriers.

The ultimate combat round thread can be found here:

http://www.thehighroad.org/showthread.php?t=292713

TexasRifleman
June 22, 2008, 01:41 PM
No, the 5.7 was designed as a pistol replacement for troops that don;t have combat MOS. It was not designed for close combat. It was designed to replace 9mm ball from a handgun.

The first public demonstrations of the x28 were done with a P90, not a handgun.

The x28 came out in initial public testing around 1995, 96.

The Five Seven handgun did not come out til around 99, 2000.

The round was developed for the P90 PDW, then later adapted to handguns when agencies wanted their SMGs and handguns to use the same round.

GunTech
June 22, 2008, 01:44 PM
Here's something to think about vis-a-vis 5.7x28. How many people think the 22 hornet would make a good combat round?

22 hornet will launch a 32gn projectile at 3000 fps
5.7x28 can only 2350 fps with the same bullet weight (SS190AP)

GunTech
June 22, 2008, 01:45 PM
The first public demonstrations of the x28 were done with a P90, not a handgun.

The x28 came out in initial public testing around 1995, 96.

The Five Seven handgun did not come out til around 99, 2000.

The round was developed for the P90 PDW, then later adapted to handguns when agencies wanted their SMGs and handguns to use the same round.

Exactly, and the PDW was supposed to replace the handgun - hence the 5.7x28 (in the PDW) was meant to replace the 9mm pistol

TexasRifleman
June 22, 2008, 01:46 PM
Here's something to think about vis-a-vis 5.7x28. How many people think the 22 hornet would make a good combat round?


Here's something to think about...

Is anyone making a 50 round capacity submachinegun shooting 22 Hornet that uses a bullet designed to penetrate body armor?

You're hung up on velocity and energy, but that's not really what this round was developed for.

It was specifically designed for use in a submachinegun with a bullet designed to penetrate body armor.

GunTech
June 22, 2008, 01:47 PM
Just for reference, I thought this comparison would be illustrative.

From left to right:

5.7x28, 22 K Hornet, 5.56x45, 6.8 SPC, 6.5 Grendel, 6.5x45 Cz, 7.62x51

http://guntech.com/ammo/comparison-5.7-308.jpg

rbernie
June 22, 2008, 01:51 PM
I don't think anyone is dumb enough to think that it's some kind of Battle Rifle round.


Well, from post #1:

The military would just have the 5.7x28, with larger 7.62x51 and 12.7x99 machine guns providing support from machine guns and sniper rifles.

TexasRifleman
June 22, 2008, 01:54 PM
Well, from post #1:

Exactly, the OP didn't intend this as an argument for the x28 as a main battle round, he asked why the things that made the 5.56 appealing would not simarly apply to x28.

I got the idea he was poo pooing the reasons to move to 5.56 in the first place.

If the arguments for moving from .308 to 5.56 were valid, why not apply the same thing to x28, then down and smaller from there to absurdity.

And, if those reasons don't apply in the 5.56 vs x28 argument then maybe they didn't apply so much in the .308 vs 5.56 argument.

Maybe I read it wrong but I didn't get the idea he was proposing x28 as the end all and be all so much as questioning the original reasons for abandoning .308

PercyShelley
June 22, 2008, 05:18 PM
Laugh though we may now, HK looked very seriously at 4.6mm assault rifles (the G11 and HK36) before they developed the MP7. Some hyper-velocity gimmick you protest? No, both of those rounds developed substantially less velocity than 5.56 NATO ball loads in addition to having smaller, lighter bullets.

Go figure.

zinj
June 22, 2008, 10:00 PM
In Vietnam the 5.56x45 was actually shown to be 11% more lethal than the 7.62x51 - exactly because most combat operations were meeting engagements and ambushes at relatively short range.

How was this figure determined? Not doubting the figure; but was this ratio calculated per round, per engagement, or what?

Laugh though we may now, HK looked very seriously at 4.6mm assault rifles (the G11 and HK36) before they developed the MP7. Some hyper-velocity gimmick you protest? No, both of those rounds developed substantially less velocity than 5.56 NATO ball loads in addition to having smaller, lighter bullets.


Yes, but they were never fielded. History is littered with dozens of examples of technologies that saw significant amounts of R&D poured into them before it was realized they didn't even meet the performance set by the contemporary standard; doubly so when they were given government funding.

GunTech
June 23, 2008, 12:43 AM
Fair question.

IIRC, the 11% figure comes from casualty reports. It is quoted in several of the Ezell books. I'll do some digging with regard to methodology.

HorseSoldier
June 23, 2008, 01:48 AM
Whole premise of the thread is based on a faulty supposition that you can keep going lighter and lighter on a combat round.

We know that combat cartridges are a compromise in weight/volume, kinetic energy and mass, recoil, etc.

We also know 7.62x51 was pretty much recognized as a flop in general service rifles here in the US as soon as Ordnance's cool theory about infantry combat met the reality of the AK-47 (ignoring for the moment the various people here in the US and elsewhere who recognized how vapid the arguments for 7.62x51 were in the first place, based on data going back to, oh, 1917 or so . . .).

5.56x45 was a better optimization. The goal is finding the sweet spot, however, not infinitely paring down bullet mass and velocity.

GunTech
June 23, 2008, 02:06 PM
It also depends on what you are seeking. Some of us are interested in the possibility of a universal military round, that can be used for Rifle, carbine, DMR and MG - replacing both 5.56 and 7.62.

Obviously such a round will be a compromise - but as already noted, every round is a compromise. But the 6.62x5 is basically a variation on the hundred year old 30-06, and even the 5.56x45 is 50 years old. Moderate weight bullets with good BCs can outperform the 7.62x51 at longer ranges with less weight and recoil, and equal or better 5.56 at shorter ranges.

The idea round is light in weight, accurate, has little or no recoil and is effective past 100 yards. You aren't going to get everything you want. But you should be able to streamline logistics and be able to get a round that does everything pretty well - at least as far as an infantryman is concerned.

GunTech
June 23, 2008, 02:07 PM
Of course, we are basically now getting back to the same material already covered in the 'ultimate combat round' thread.

buzz_knox
June 23, 2008, 02:25 PM
It was specifically designed for use in a submachinegun with a bullet designed to penetrate body armor.

The PDW concept was intended to produce a weapon that would be easy to use by support troops and was able to penetrate the armor worn by the enemy. The P90 and MP7 epitomized one answer to the concept, by providing high capacity light recoiling automatic weapons that had greater range and ease of use than the MP7. Other answers included saboted 9mm rounds in machine pistols, cut down ARs, etc.

It's worth noting that body armor technology has improved greatly since the 5.7 and 4.6 were designed. There's substantial question as to whether it can currently fulfill the mission it was designed.

MTMilitiaman
June 23, 2008, 03:18 PM
Maybe I read it wrong but I didn't get the idea he was proposing x28 as the end all and be all so much as questioning the original reasons for abandoning .308

DINGDINGDING! We have a winner!

At least someone can read...

I already specified that I was playing Devil's Advocate here. I am not a big enough poodle shooter fan to actually propose we go any lower. But the logic is the same.

First you observe that most combat takes place well within the effective range of the currently issued cartridge and that modern infantry has to carry a lot of crap, so reducing weapon load is a good idea. Then you propose a compromise to a small, shorter range cartridge that is still likely to be effective at the majority of current engagement distances while providing both lighter weight and less recoil. Then you use a lot of fancy wordage that politicians are likely to be impressed by, even if they don't completely understand, to describe the construction and effects of the projectile and exaggerate its effectiveness, and awe them with some exploding watermelons, explaining that it will do the same thing to the human body. And with the right political connections, wha-lah! The 5.56 is now your standard infantry cartridge. O, did I say 5.56? I meant 5.7 :uhoh:

The 5.7x28 is actually intended to fill roughly the same role as the M1 Carbine. It is my understanding that this rifle was never intended to be standard issue on a large scale either, but despite claims of it failing to penetrate thick Korean winter garb, most units seemed to find it effective enough, and liked its light weight. If my understanding of history is correct, the Carbine, originally intended primarily for officers and REMFs as an alternative to the 1911 Colt, then found its way into Armored Cav and Airborne troops, and then into the general populace. I could be wrong here, but again, the philosophy was similar to the creation and adoption of the 5.56--sacrifice range and power for weight and controllability under the pretense that the round will still be effective at commonly occuring engagement distances.

Acknowledging that the average engagement distance in Iraq is rumored to be under 100 yards, the 5.7 doesn't seem like much of a stretch. Especially since nobody is suggesting we give up the 7.62 and .50 BMG in the support roles.

Joe Demko
June 23, 2008, 03:24 PM
7.62 x51 wasn't considered a success when it was the general issue round. It's not coming back as such, either.
Whatever replaces the 5.56 will be an "assault rifle" cartridge of some type.

buzz_knox
June 23, 2008, 03:32 PM
The problem with this line of argument is that it misses the fact that the 5.7 on its face does not fulfill the necessary requirements for a service caliber that had largely been agreed upon before and after WWI, WWII, and Korea. The 5.56, by contrast, met those requirements. One can argue over how well it does, but the 5.7 would be a nonstarter even as an "intellectual" excercise.

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