5.56 vs. 6.8/6.5 continues

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WillBrink

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Some basic rehash of articles we have all read before, but it appears the debate about "upgrading" the 5.56 continues:


M4 Round Has Strong Competitors

October 10, 2008
Tactical Life|by André M. Dall'au

Eugene Stoner and ArmaLite designed and built a lightweight, powerful, small-caliber shoulder weapon after the Army asked for help to develop a 5.56x45mm chambered military rifle in 1957.

The Army, looking ahead to a jungle war in Southeast Asia, picked the lightweight design to equip its new, highly-mobile soldier. But the Army did not fully adopt the specific design requirements that made the original AR-15 operate effectively.

No one recognized that the ball powder substituted by the Pentagon had a greater fouling effect on the AR bolt assembly and chamber area. In addition, troops were not properly trained on how to clean their new rifles. The result was a weapon that was susceptible to jamming in the field, giving the new rifle a bad reputation right off the bat.

The poor initial performance, together with the marginal incapacitating ability of the 5.56 round, led to doubts about the Stoner design that linger today. But the mobile warriors of today are frequently getting in and out of vehicles and need a shorter weapon. The loss of active barrel length in the M4 further cuts the overall effectiveness of particular loads of the 5.56 round that many already considered to be too small and weak.

Recognizing the dilemma, military and civilian manufacturers are developing rounds for the AR platform that could bridge accurate lethality and shorter barrels. Two different approaches are strong contenders: the 6.8 SPC (Special Purpose Cartridge) and the 6.5 Grendel.

Both the 6.8 SPC and 6.5 Grendel have a greater potential for immediate lethality than the 5.56, based on a heavier bullet traveling at a comparable speed. During tests, shots taken at distances ranging from 50 to 75 yards with the 6.5 Grendel at medium-sized wild hogs produced many first-round lethal hits, as well as immediate incapacitation. The bullets did not exit but fragmented during passage through the tissue.

The accuracy of 6.5 Grendel and 6.8 SPC was excellent. The groups for each caliber met or exceeded previously published data. The ability to stay on target during full-auto fire was achievable and far exceeded any similar .308-caliber weapon on hand for controllability. Our overall conclusion is that both the 6.5 Grendel and 6.8 SPC demonstrate superior effectiveness when compared to the 5.56 -- transferring more energy using a larger, purpose-formed bullet.

The 6.8 SPC is a well-engineered combination of velocity, accuracy and reliability for combat engagements up to 500 meters. With a trajectory very similar to the .308 WIN, the 6.8 SPC provides almost 50 percent more downrange, terminal-energy than the 5.56 NATO at 100-200 meters. However, at distances greater than 400 yards, performance of the 6.8 SPC is inferior when put up against the .308 Win or the 6.5 Grendel.

The 6.5 Grendel bullet is designed for energy retention during flight and has about twice the mass of the 5.56 NATO, with ballistics superior to the soviet-era 7.62x39 mm round. It maintains a devastating impact on tissue at longer ranges. The flat-shooting round has demonstrated one minute-of-angle accuracy beyond 600 meters, where the performance of the 6.8 SPC falls off.

Overall, both the 6.5 Grendel and 6.8 SPC offer similar hard-hitting short-and-intermediate range performance with .308 accuracy out to intermediate ranges. The 6.5 Grendel has the edge past 600 meters. Given a choice, I would take the better ballistic bullet of the 6.5 Grendel, which has incapacitating lethality for most tactical situations from CQB to out beyond 600 meters. However, the logistical support for the 6.5 Grendel and 6.8 SPC has been inconsistent. In addition, the demonstrated ability of the 5.56 green-tip to penetrate light armor and steel plate better than the 6.5 Grendel or 6.8 SPC will be of interest to operators who might have to take on technicals when under fire.

Although no single caliber will provide the operator with a solution to every tactical problem, many warriors interviewed would still take the M855 5.56 due to overall satisfactory performance and ammo availability. One of the important aspects of the "is the M4 good enough" argument is to ensure that the "real" trigger-pullers have the loudest voice and overriding opinion about what works in the field.
 
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7point62

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It goes round and round, don't it, like 45 ACP vrs 9mm. 6.8 is the big compromise. Like the article sez, the trigger-pullers and door-kickers are the ultimate judges.
 

11B-B4

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for me 5.56 hands down. you can carry more ammo and less recoil plus with the guys we're shooting weighing between 90-140 lbs on average i dont think you need much knock down power.

But thats just one opinion. I think all the 6.8 guys are just ak lovers. fuckem
 

pardus

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for me 5.56 hands down. you can carry more ammo and less recoil plus with the guys we're shooting weighing between 90-140 lbs on average i dont think you need much knock down power.

But thats just one opinion. I think all the 6.8 guys are just ak lovers. fuckem

Or how about us 6.8 guys are people that think we need a round with better overall performance than a 5.56 and fuck anyone who thinks otherwise?

Understand?



Might want to watch what you say around here that is insulting to members of this board, just some friendly advice... ;) :2c:
 
A

arizonaguide

Guest
Or, to continue Pardus' thought a little further...I'd like to quote my ALL time favorite classic: (11B, check it out, this IS classic wisdom...not that the 5.56 is NOT a beautiful weapon and all, but: )

Well, Rav, it's like this. I'm old. That makes me persnickety. I bet on horse races after they've been run. That's why on this last deployment I carried a regular old, rack-grade, solid plastic stock, M14 that had been made by Winchester in 1958. Stoked it with AP exclusively. Used iron sights out to and including 700M. It ain't a "death-ray" but it'll do till one gets here. Total failures of any kind: 0.0

I require two things of my weapons: 1) Reliable as sunrise. This is first and foremost. Non-negotiable. 2) As accurate as possible without violating requirement #1. Must shoot Minute-Of-Hajji, day or night, rain or shine, world without end, amen. 3) The round has got to be able to do the job when it gets there. Is there anyone who retains any lasting doubts about 7.62x51mm in this regard?

Truth is, I have seen enough aluminum gim-cracks, plastic goo-gaws and carbon-fiber whizz-bangs for one life-time. Enough to know that the summbitches asking me to bet my life on it won't be anywhere to be found when it gets upgefucht. I'd rather carry a few extra pounds and have the fuquer work when I need it, than go light with something that fails at random intervals.

NOT exactly the 6.8 being discussed...but you get the idea (same theory anyway)!

and Kinda "corney", but good 6.8 round info:
[ame="http://www.youtube.com/watch?v=3zMpN_-pcas"]YouTube - Future Weapons: The Barrett M468 Assault Rifle[/ame]
 

11B-B4

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Or how about us 6.8 guys are people that think we need a round with better overall performance than a 5.56 and fuck anyone who thinks otherwise?

Understand?



Might want to watch what you say around here that is insulting to members of this board, just some friendly advice... ;) :2c:

I didn't think preference of a caliber was insulting. Like i stated above its just one mans opinion. I wasnt taking a personal stab at anyone im just kinda tired of the debate. And yes you can tell me to fuck off too. I take personal offense to just about nothing :)

Im sure most of us have been shot at before and watching 7.62x39 tracers rainbow in like paint balls at night and being able to dodge them from 300m makes me want something faster to shoot back at the rags with

the 6.8 out of a 14.5" tube is going at 2470fps 5.56 is moving at 2900 thats moving 18% faster and the larger diameter of the 6.8 slows down faster in the air than a 5.56 62g

Also iv'e never seen a terrorist wearing chest harnesses. I know i entered the war later than some and that may have been an issue back then but now its not.
 

MontereyJack

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Many of you have already read this report. For those that haven't I can email it to anyone who asks. It's a must read for anyone wanting to debate the effectiveness of the 5.56mm round.

Time for a Change. U.S. Military Small Arms Ammuniton Failures and Solutions. Written by LCDR Gary K. Roberts, USNR. Dated May 21, 2008.

Here is a quote from page 17 of the study,
"6.8 mm offers superior terminal EFFECTIVENESS compared to 5.56 mm in all environments, including CQB & Urban, especially when fired from short barrels.


Unlike 5.56 mm, 6.8 mm continues to demonstrate good terminal performance even after defeating common intermediate barriers, such as glass, walls, and automobiles, as well as loaded AK47 magazines, like those frequently worn in chest pouches by terrorists."



 

11B-B4

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Or, to continue Pardus' thought a little further...I'd like to quote my ALL time favorite classic (sorry to keep repeating this one...but I still love it: (11B, check it out, this IS a classic that should be headed...not that the 5.56 is NOT a beautiful weapon, but: ))



NOT exactly the 6.8 being discussed...but you get the idea!

Im fine with the 5.56 m16 platform. As long as its maintained its a great carbine. But im also one of the guys that thinks too much is just too much. Like the 416 for instance it can shoot underwater :) cool. For Seals and SF dive teams great kit. For regular ground pounders just seems like too much money to spend on something that you dont really need and will probably never encounter.
Ive done some water ops in recon but dont ever see the need for the training given the current AO in iraq. Some guys might get into it in the two rivers but hopefully not (gross). If we were in a war like vietnam where there was alot of rivers and streams id say go for it. I just dont see the need. Why I say stick with the 5.56 because theres alot of data out for it and people know it and work well with it. Id have to really shoot the 6.8 to love it and i probably wouldnt anyway unless i could stay on target like i could with recoil from a 5.56. If recoil was the same as 5.56 id probably go for it i guess. I just think from a carbine you need good follow up speed and i dont think the 6.8 is as good as the 5.56 in that specific respect. As far as medium range work like an SPR sure... go with the 6.8 but for off the rack work 0-300m i think the 5.56 is fine, but again just one mans opinion.

Edit: Also the standard gas system is quieter and smoother than the piston system when used with sound suppressors. Also a .260-.311 bore on a can is quieter than a .340-.360 bore and im a suppressor manufacture so thats another concern of mine, probably not of most people

Im out of this debate
 
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arizonaguide

Guest
7.62NATO.
Cheap, available, flat shooting, effective at range....correct?
But that's a different thread.

and Kinda "corney", but good 6.8 round info:
I Was talking about (in the video) the rounds comparison, the M16's effectiveness history, and the definition/redefinition of concealment/cover. (not about shooting the Berrett (or 416) underwater).

ENERGY:
.223 @ 200yds = 648
7.62x38@200 = 882
6.8 @ 200yds = 1163 (better!)
.308 @ 200yds = 1930

AND, MOST FRONTAL AREA (to transfer that energy)
.223in
.277in (+/-)
.308in

Hmmmm, now which are readily available currently? (7.62 NATO, just sayin.)
 

AssadUSMC

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To me this is kind of like when .40 S&W came out. Big numbers, similar package, etc. etc. Personally, I HATE .40. Too much recoil for what it is, too much blast. Either give me a 9mm that I can put lots of rounds on target with good accuracy or give me a .45 (I prefer .45 if I have a choice). Given that logic, I'd say I'm a 7.62 guy.

The other big issue is the supply chain. Sure small units, contractor companies, etc. could transition to 6.8, but it'd take YEARS for the big mil to do it. Also, while I know NATO is not the important figure it used to be, I'm sure some interoperability with our allies would be a big topic.

Just my $1.05.
 
W

WillBrink

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5.56 is moving at 2900 thats moving 18% faster

Are you sure about that figure? Is that an M855? One of the major criticisms of 5.56 coming out of the 14.5 tube is the velocity is below what's required for it to perform as intended. Regardless, 2900 is only 200ft/ps above the approx 2700 required for the bullet to perform as designed vs just poking clean little holes in people, so the effective envelope for the rnd is very narrow:

"There has been much criticism of the poor performance of the round, especially the first-round kill rate when using firearms that don't achieve the velocity to cause fragmentation. This typically becomes an issue at longer ranges (over 100 m) or when penetrating heavy clothing, but this problem is compounded in shorter-barreled weapons. The 14.5-inch (37 cm) barrel of the U.S. military's M4 CarbineM4 Carbine

..., if the round is moving too slowly to reliably fragment on impact, the wound size and potential to incapacitate a target is greatly reduced.

Recently, advances have been made in 5.56 mm ammunition. The US military has adopted for limited issue a 77-grain (5.0 g) "Match" bullet, type classified as the Mk 262Mk 262

The Mk 262 is a match quality 5.56x45mm NATO round manufactured by Black Hills Ammunition made originally for the Special operations.The heavy, lightly constructed bullet fragments more violently at short range and also has a longer fragmentation range.

... the ammunition has found favor with special forces units who were seeking a more effective round to fire from their M4A1 carbines.

http://www.absoluteastronomy.com/topics/5.56_x_45_mm_NATO
 

pardus

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I didn't think preference of a caliber was insulting. Like i stated above its just one mans opinion. I wasnt taking a personal stab at anyone

Your preference of caliber has nothing to do with this.

Read this...

"I think all the 6.8 guys are just ak lovers. fuckem"

You said everyone who like the 6.8 are just AK lovers and "fuckem" That's insulting to every member here who is a "6.8 guy" what ever that is.

Like I said, just watch what you say and how you say it, meaning doesn't always convey the way you intend it online.

Your input is very welcome, I don't want you to think otherwise.
 
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arizonaguide

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And the "AK love" logic/corelation doesn't wash either:

ENERGY:
.223 @ 200yds = 648
7.62x38@200 = 882
6.8 @ 200yds = 1163 (much better at range than AK or M4!)

Although Will has some points about fragmentation, when it works. still....1163@200.
 

Diamondback 2/2

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Blah blah blahhhhhhhhhhhh!

If I ever make it to one of these ShadowSpear shoots, you guys can grab your 6.8’s 7.62’s and what ever else. I’ll bring my NM AR15 and a handful of 77’s and we will square off at 600 meters. See who walks away with the least amount of holes. “if anyone walks away” :p

That way we can all finely agree that this discussion is the dumbest one to be having;)

Big Army is not going to change rifle’s or calibers, maybe better bullets. But that is still something that will take forever and a day in the real world! Mean while joe is out killing the shit out of our enemies with shitty M855 and 1/7 twist M4’s at whatever range he needs to!
 

shortbrownguy

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Blah blah blahhhhhhhhhhhh!

If I ever make it to one of these ShadowSpear shoots, you guys can grab your 6.8’s 7.62’s and what ever else. I’ll bring my NM AR15 and a handful of 77’s and we will square off at 600 meters. See who walks away with the least amount of holes. “if anyone walks away” :p

That way we can all finely agree that this discussion is the dumbest one to be having;)

Big Army is not going to change rifle’s or calibers, maybe better bullets. But that is still something that will take forever and a day in the real world! Mean while joe is out killing the shit out of our enemies with shitty M855 and 1/7 twist M4’s at whatever range he needs to!

Game, set, match...
This reminds me of the great debate of 9mm vs .45, Baretta vs. others.
Maybee we should spend more time worrying about basic marksmanship, then the next big thing that aint gonna happen anytime soon:2c::cool:.
 
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arizonaguide

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Blah blah blahhhhhhhhhhhh!

If I ever make it to one of these ShadowSpear shoots, you guys can grab your 6.8’s 7.62’s and what ever else. I’ll bring my NM AR15 and a handful of 77’s and we will square off at 600 meters. See who walks away with the least amount of holes. “if anyone walks away” :p

Sounds good. But let's make that 900 or 1000 meters, behind an automobile or sand berm. :cool:

I'm not bashing the 5.56 exactly, just sayin 7.62 numbers are better, and it's available. Some folks (SOF not "Big Army") ARE using M-14's, correct? Does the "new" SCAR (the "short term" future?) not come in 7.62 (also) for a reason?

I mean, you're right ...we could have not even started this thread..as the 6.8/6.5 is YEARS away, if then.
But we did, so...
 

pardus

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Guys with 10+ years in won't see it and guys just enlisting may still not see 6.8mm.

My guess is by the time the Army gets serious about a change in caliber we'll be looking at another technology, rail gun, laser, darts, fucking plasma lol

I love using the 5.56, it's very accurate and with no recoil, it's just a POS at trying to punch through anything other than flesh, if I had my druthers I'd take a larger cal, I don't so I'll take the 5.56 and I'm happy with that.

But mark my words everyone, 5.56 doesn't do shit to ZOMBIES! you've been warned!
 
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arizonaguide

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Exactly...freakin Zombies.
Check out the future:
http://www.dtic.mil/ndia/2008Intl/Spiegel.pdf <<<< HERE.
http://en.wikipedia.org/wiki/Lightweight_Small_Arms_Technologies <<Program Description

"The Lightweight Small Arms Technologies (LSAT) program is funded by the Joint Service Small Arms Program, with the goal of significantly reducing the weight of small arms and their ammunition."

Design of an LSAT battle rifle began in 2008. Half way into 2008, the designs are nearing completion. The rifle designs are made to use the same cartridge as developed for the LMG, and this means separate rifles are being designed for the cased and caseless cartridges. Design began with seventeen concepts; after the concepts were investigated and trade-offs were analysed, only two remained for the cased round, and two for the caseless round. The concepts involve two magazine approaches, both of which are focussed on high capacity: one uses the standard approach of placing inside the magazine springs that feed rounds into the weapon; the other uses a 'weapon powered' approach, presumably to reduce the extra weight and space that springs create in magazines. If any of the rifle designs use the same swinging chamber mechanism as the LMG, they should be well suited to a bullpup layout, since the forward ejection of the push-through feed-and-ejection mechanism could easily be extended to achieve full ambidexterity, which is a problematic absence in most bullpups. Even in other configurations, the push-through mechanism lends itself very well to ambidexterity: the G11 demonstrates this. The rifle designs are undergoing the same simulated, structural, and kinematic analyses as the LMG."

"The LSAT program uses a 'clean slate' design and had no requirements imposed on abiding by contemporary ammunition and weapon standards. Despite this, the program is using the M855 5.56x45mm round to provide comparison with existing weapons. The program has listed scalability of the ammunition calibre as a requirement, and its pursuit of a very light company machine gun would require a larger round. Therefore, the program seems set towards a more accurate, harder-hitting round (such as the 6.5 mm Grendel or 6.8mm Remington SPC)."

AZG Engineering Inc. caseless swinecoat(tm) ammunition testbed XAZG-1: http://www.popularmechanics.com/technology/upgrade/4263421.html
 
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