# New American rifle 7.62x51mm



## The Basket (Sep 3, 2017)

Turning the clock back to the 1950s and the M16 didn't happen.
My view there is always a bigger is better attitude and now saying 5.56 can't penetrate body armour or the enemy is using 7.62×54mmR which is far longer ranged or that 5.56 don't kill like it should? Valid argument?
Maybe need a better 5.56mm round.


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## Shortround6 (Sep 3, 2017)

The 5.56 bore has a problem or two.
Yes you can use heavier bullets that have more energy and retain it better _BUT _ you only have so much powder capacity in the cartridge case so at some point you run out of oomph for heavier bullets. heavier bullets require a faster twist rifling.
The more powder you try to use in a given size bore the worse the barrel erosion is, this tends to limit the size cartridge case (amount of powder) that is practical in a military gun.
Large powder charges also mean more noise and more muzzle flash (unless you use flash suppressants, one of the things that screwed up the early M-16s) with a given length barrel.

The 7.62 also has a few problems, weight and size of guns needed are one.
It is harder to train troops the use the larger and harder kicking rifles (at least according to modern thinking) and the 7.62 is useless in light weight automatic weapons. I would also note that using the standard 150 grain flatbase or 147 slight boattail the down range performance is not all it could be either. Sniper ammo was often 172 grain or 168 grain match ammo so don't use anecdotes of sniper engagements to justify extreme long ranges for ball ammo.

The US really missed the boat when it forced the British to give up on the .280 British as it gave decent down range performance with lighter recoil than the 7.63 X 51 although full auto fire was still pretty much a waste.

Depending on your bullet making technology in the 1950s you may be limited as to how tricky you can get with bullets/calibers.

I would also note that you better figure out what you want the bullet/cartridge to do and not try for the singing, dancing, tells jokes and washes windows requirement. (light recoil, flat trajectory, armor piercing, high lethality, light weight ammo and rifle) 

Early 5.56 killed pretty good against unprotected targets (bullets tended to flip pretty easy) but then they changed the rifling twist and went to a bit heavier bullet. Bullet tended to stay point on instead of flip and wounding/killing power went down even if barrier penetration went up a bit. Heavier bullet did retain energy down range a bit better though.


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## parsifal (Sep 4, 2017)

ive never been convinced about the argument that the lighter shell 5.56mm used in the M-16 was easier to train with. I always found it harder actually. 

The M-16 is considered a very accurate rifle, with published effective ranges of 350-500m and an "accuracy rating" of 4.3 in at 100m. The AK-47 by comparison has a nominal effective range of 300-450m and an "accuracy rating" of 6.9in over 100m

The L1A2 in Australian Army service had a rated effective range of 600m. I don't know of an accuracy rating for the FN FAL family, undertaken with confirmed military conditions like the other two, but I have read some claims that it is accurate to 1.5" over 100m. The problem with that is that ther is no way of confirming the condition under which the tests were carried out.

My impression was that the SLR felt like a a more accurate piece of kit. It certainly was no harder to learn on than the armalite. ive never fired the AK-47.


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## The Basket (Sep 4, 2017)

The Japanese went from 6.5mm to 7.7 for the same arguements ad infinitum that we can mention here. 
Nothing changes! It's like fashion.
The ability to go through body armour is more type of bullet than calibre.
Although in the Carcano thread, Shortround did mention lack of range of the intermediates so again it's wether you want to go cqb and kick doors in or go for 500 metre shots? Horses for courses.


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## Shortround6 (Sep 4, 2017)

Without knowing the conditions of a test it is impossible to compare different test results.

In this case we have 3 different guns, each firing a different cartridge and at least two different "test" methods. which tells us something about each one but not a lot. 

I would suspect the low accuracy rating of the AK-47 has as much or more to do with the rifle (and sights) than with the cartridge. 

Although I have heard that most military 7.62 X 39 is rather poor stuff. I would reserve judgement until some was fired out of some sort of test gun that eliminated some of the problems with the AK-47 and clones. 

The M16 has the flattest trajectory, at least over the first few hundred meters which helps eliminate range estimation errors for most combat. Long range use was problematic in that the early bullets lost power at longer ranges (being by far the lightest bullet) and was much more susceptible to cross winds. Doesn't do much good to have the least drop if you get blown sideways by a gentile breeze. 

max effective range is always a bit of a judgement call and without knowing the criteria used for the judgement it is also difficult to compare weapons. 

As an extreme example I once pulled pit (handled the target) for a shooter using an M1 rifle in a match. He shot very well at 800 and 900 yds but at 1000 yds he was all over the target with (if memory serves) 17 bullets out of 22 going sideways to some extent (oval holes instead of round and some showing the full side silhouette of the bullet). Now define effective? His target score was miserable yet in a theoretical combat setting he had just placed almost 20 projectiles ( a few misses) in a roughly 6 ft by 6 ft area at 1000 yds. which I would say would be rather dangerous for an enemy even if not one shot=one kill. rather obviously his rifle/bullet combination had reached it's limit and another 100yds would have seen bullets all over a hill side as bullets tumbling end over end scatter pretty quickly. 

I will freely admit that this was at a known distance and that 6 X 6 ft buff (tan/off white targets) with large black bullseyes against a green background show up rather well in daylight and so don't represent combat conditions even as regards to being able to see targets let alone anything else. 

When talking about a hypothetical rifle/cartridge we need to identify what we want the rifle to do. My own criteria for my first 6.5mm rifle was equal accuracy to a .308 using match bullets, less recoil, and equal trajectory and wind drift for example. a competitor at these matches was using a rifle chambered for a 6mm benchrest cartridge using very light bullets. On a calm day he and I were very close and he might have the edge. If the day was even puffy winds at just 5-10mph a few of his bullets (out of 40 per match) would go into the 9 ring and my heavier bullets stayed inside the 10 and I would win even though his gun could fire a tighter group on the calm days. My bullets weren't blown around any more than the .308 bullets at this range (300 yds). 

The guys using .223/5.56 rifles were using 68 to 77 grain bullets to try to fight the wind and while some 5.56 military ammo used such bullets they were not common and in fact were non existent in the late 50s and early 60s when the M16 was adopted. 

to repeat, when looking at a new rifle/cartridge identify what you want it to do, and try using numbers, not saying that it should be better than rifle/cartridge X without saying how much better.

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## yulzari (Sep 4, 2017)

As ever, the first thing is to decide what you want your round to do. Then develop something that will do it. Then something that will make it do it reliably and not need a bearer to carry it for you. 

Lastly the bean counters tell you that you can't afford it and you look on the market place for the nearest thing to it that you can afford and uses the old round for which, the bean counters remind you, you have millions in store. Thus the Lee in British service went from opposing single shot black powder opponents to opposing automatic rifle armed ones.

BTW the L85A1 took ten odd years to develop into production plus many more to get it right with the L85A2. The Lebel took 3 months to be ready for production from a standing start. Just don't mention the necked down Gras ammunition.

Really it is not interplanetary rocket science. The principles were worked out well before German Vicky popped her clogs and only the materials and chemistry have changed. Semi automatic rifles began a decade before WW1 and the pre WW1 6.5mm ammunition only needs adding better bullets and the case shortened a touch to benefit from modern chemistry. Like the bicycle it is a mature technology adjusted for modern materials.

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## The Basket (Sep 4, 2017)

No development needed as the rifle will be off the shelf so the rifle already exists.
SCAR-H? HK 417? Or dust off some museum G3 and FALs.


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## Shortround6 (Sep 4, 2017)

The Basket said:


> No development needed as the rifle will be off the shelf so the rifle already exists.
> SCAR-H? HK 417? Or dust off some museum G3 and FALs.




I am getting confused,

Your first post 


The Basket said:


> Turning the clock back to the 1950s and the M16 didn't happen.
> My view there is always a bigger is better attitude and now saying 5.56 can't penetrate body armour or the enemy is using 7.62×54mmR which is far longer ranged or that 5.56 don't kill like it should? Valid argument?
> Maybe need a better 5.56mm round.



which is it, turn back the clock and discuss what the US should or should not have done in the 1950s or talk about which off the shelf rifle they should buy in 2017/18?? 

Part of the US problem is trying come up with a helicopter/APC friendly rifle/carbine (short) so after you take a hacksaw to the museum G3 and FALs what have you got ?????


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## The Basket (Sep 4, 2017)

Choosing an off the shelf design makes sense from a view of value as no development costs and you know the rifle is ready to go. I only used the FAL as an example of what is available. Although not sure if it's still in production but if you want a full on 7.62mm rifle then the FAL does great. 
A bullpup could marry short length and long barrel but I top off my head don't know any 7.62mm bullpup. 
The British used the FAL for battle rifle and the Sterling as a cqb and it feels that the Americans may fall into same place if they go for a full on full fat 7.62 rifle.


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## Shortround6 (Sep 4, 2017)

The Americans are still stuck on the one gun (or one platform) does all. Just use different barrels to go from personnel defense weapon to sniper rifle (exaggeration but a grain of truth) and without different ammo short 7.62 barrels have a lot of blast, flash and loss of velocity. 

Of course the one gun wonder takes so long that various units/special forces adopt different weapons so everything becomes a hodgepodge anyway.


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## Torch (Sep 4, 2017)

I'm sorry I sold my SCAR 17 in a .308 due to the previous administration policy attempts. Please not a political post but I found that rifle to be accurate,reliable and with a couple of mods was a damn good rifle. I've had a PTR 91,a SIG 716, I'd take the SCAR any day.


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## The Basket (Sep 4, 2017)

A HK 417 variant has already won a US army competition. It was for the compact semi automatic sniper system based on the German G28.
It is designated as the *M110A1.*
The HK 416 is in USMC service so HK certainly gaining support in US military


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## parsifal (Sep 4, 2017)

How do these alternatives stack up on cost?


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## Robert Porter (Sep 4, 2017)

I think an important point is being missed, with the exception of snipers, range was not and is not an issue. One thing Vietnam taught us was that 99.9999 percent of the rounds fired in combat are only loosely aimed and are more suppressive fire than aimed take down fire. Combat troops in any conflict from Vietnam forward, again with the exception of snipers, typical engagement distance is measured in tens of feet not 1000's of feet. 

Your typical infantryman, British, American, whatever is NOT a marksmen. Instinctive Point of Aim is still taught to combat troops and with good reason. 

Now personally I favor a larger heavier round. But the plain fact is the larger the round typically the heavier the weapon and in real terms the less ammo can be carried for the same weight. With the advent of modern body armor I do believe a better, heavier round is overdue. However the technology to create 5.56 penetrator rounds that would defeat any existing body armor, unfortunately or fortunately depending on your view point that technology is forbidden. 

Years ago a company I worked for did some serious consulting with Hornady. They had developed a .22 long rifle round that went straight through top of the line body armor. It ate the crap out of a barrel, and was expensive as all get out but at ranges up to 200 feet it would punch a hole in anything that folks were able to wear. So size and weight of a round are not the _only _factors contributing to knock down power. They sure do make a big difference however when all other things are equal. 

We sold them a very accurate timing circuit they used with laser screens to analyze ballistics and trajectory data. It was a fun project!


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## parsifal (Sep 5, 2017)

That's turned out to be a very contentious issue in other threads....what emphasis is placed on aimed fire over sheer volume of fire.

In both the Australian Army and to an extent the IDF, the emphasis is less on volume of fire and more on making each shot count. 

We learnt this from our experiences in the jungle in a world war and also in Vietnam. Making noise in the jungle is dangerous. Expending ammunition needlessly decreases the effectives of the unit because it decreases the ability of the unit if operating any distance at all away from the supply head. Sure the distances are not that great (though the experiences of our special forces in the middle East in the more recent conflicts does emphasise the need to hit things at range), but it has always been at the heart of the Australian Army that every soldier be well trained and this means that he needs to be above average with accuracy.

The IDF, as I understand it trains to a similar standard.

not all armies train with a primary role of volume of fire driving their training. that is a uniquely American tenet.


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## Shortround6 (Sep 5, 2017)

I would note that all too often the infantry got the soldiers that nobody else wanted. 
That is to say that after the artillery, armor, air component and any other "technical" branches got what they needed form a levy of recruits the infantry got the rest as it was assumed that if a recruit could walk and chew gum at the same time the army could teach him to march and carry a rifle. 
In actual fact the infantry rifleman is one of the most difficult jobs in the Army IF your infantry is going to fight as a disciplined/effective team without relying on outside support (artillery/air strikes) _every_ time they are shot at. 

granted the infantry did get _some_ good troops and the other branches did get some duds.


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## Robert Porter (Sep 5, 2017)

I sincerely doubt it is a unique American tenant. Based on my own discussions with servicemen it seems to be a fairly standard approach. And it is not meant as a doctrine even here. Aimed fire has its place. And some degree of training is expended on that approach. It is situationally driven of course. But the facts are undeniable in terms of raw numbers including the British in the few land engagements during the Falklands. I don't recall the specific numbers but far far more rounds were expended, than casualties incurred on the enemy. 

There is something to be said about the actual emotive state of mind in an engagement. And even well trained troops will throw a wall of lead downrange when scared or startled sometimes. Less well trained troops like the civilian "security" contractors in the sandbox are not even all that concerned about where those rounds go! I cannot think of any modern conflict that did not expend 1000's of times the rounds as the casualties inflicted. 

Then we have the whole terrorist approach to "spray and pray" that is so common. This is the worst example as it tends to catch non combatants but then that is most terrorist groups stated goal. Heck the only force I can think of that fights that approach is modern police forces. And even there, there are some examples of significant overkill.


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## Shortround6 (Sep 5, 2017)

I suspect, but could very well be wrong, that just like air to air combat, in ground combat most of the "killing/wounding" is actually done by a small percentage of the soldiers firing with the bulk of the troops just firing in general direction of the enemy and few just firing enough rounds and exposing themselves the minimum amount necessary avoid to be called out on it by their squad mates. 

This makes designing or purchasing for the "average" a rather dangerous venture. You are over buying for the majority of the troops but perhaps under buying for the troops that are actually causing the majority of enemy casualties?

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## Token (Sep 5, 2017)

Shortround6 said:


> I suspect, but could very well be wrong, that just like air to air combat, in ground combat most of the "killing/wounding" is actually done by a small percentage of the soldiers firing with the bulk of the troops just firing in general direction of the enemy and few just firing enough rounds and exposing themselves the minimum amount necessary avoid to be called out on it by their squad mates.
> 
> This makes designing or purchasing for the "average" a rather dangerous venture. You are over buying for the majority of the troops but perhaps under buying for the troops that are actually causing the majority of enemy casualties?



Designated Marksmen?

T!

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## Shortround6 (Sep 5, 2017)

The term "Designated Marksmen" may be new but any outfit that had seen much combat probably had a few natural leaders (regardless of actual rank) or "go to " guys the officers relied on. Trouble in green outfits was the officers didn't know which troops to trust and the troops didn't know which officers/non-coms to trust.
Performance on the range is not a guarantee of performance in combat except in the negative. Troops that can't shoot on the range will NOT miraculously become good shots in combat. Someone who posts good scores on the range may or may not freeze in combat or otherwise perform sub par.


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## The Basket (Sep 6, 2017)

Also mentioned is the M16 direct impingement gas system.
They want either short stroke or long stroke gas piston.
I get the feels that the M-16 was never truly loved and most of the changes are simply a stick to beat it with. Replacing the M-16 with another 5.56 is silly but it can be replaced with a 7.62 which can do things the M-16 can demonstrably not do.


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## parsifal (Sep 6, 2017)

One thing to remember is that wounding a man in a western style army is probably more detrimental to unit efficiency and costly than killing him outright. It generally takes anywhere from 6-10 guys to triage, and then evac the injured soldier. If the casualty needs to be airlifted there is a risk of losing that helo, and in any event is using that asset when it might be needed for some other task as well. Losing a man outright is detrimental to unit morale and leaves a gap in squad capability, but at least few or no resources are used to further treat that man.

Moreover, depending on the standards that apply to casualty classification, it might be years, if ever before that man can return to service. My stepfather fought at Stalingrad, but was wounded by a sniper before the encirclement. He was shot in the arm, not that badly in his words (though he was decorated for his trouble). Despite this he did not return to service until June 1944, after the emergency in the west became apparent. Even so he was rapidly press ganged into the new 6A and shipped off to Rumania and finished up in Hungary (or possibly Austria….Im unsure). Point is though, that snipers bullet put him out of action completely for more than a year, and even after he returned to service he could not carry a rifle. He was essentially “walking wounded”, press ganged back into support echelons as Germany went through the most acute of manpower shortages.

From a resource management point of view, it was more costly to wound my step father over killing him. Im glad that he was not killed incidentally.

A 5.56mm shell is purported to be less lethal than a 7.62mm round. Ive yet to be convinced of that, but if true, its probably a more effective weapon than the 7.62mm round from the point of view of curtailing operational efficiency, but only against an enemy that cares about its soldiers and its wounded. Against an army of madmen, intent on killing itself and fighting to the death, usually involving some form of self immolation like blowing themselves up, the shoot to wound strategy simply falls apart. In that scenario, you need a first round kill at maximum range, on a scale within the force structure. That’s where the emphasis on shooting accuracy over shooting volume comes into its own, and might be some of the reason our guys have been judged the most efficient units by the (I think) US military for nearly every year of deployment since 2001.


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## Shortround6 (Sep 6, 2017)

The M-16 saga was a comedy of errors in the beginning which established a bad reputation that took decades to overcome. If then, 
was it the rifles fault the army failed to issue cleaning kits or cleaning rods? Which genius told the troops it was self-cleaning? The last minute powder switch and so on. 

Yes it had a few mechanical faults but not as many as some people believe.

The Army is in the same position it was in the early 30s with the M1 rifle. Too many 5.56 rounds and too many 7.62 rounds in stock to change to a cartridge that will offer any improvement over either. So any new rifle is crippled in one way or another. In fact many new rifle rifle requirements are hampered by the need to use existing magazines. 

7.62 ammo is large and heavy limiting the number that can be carried, in has too much recoil to make a full auto gun even remotely practical. It is less practical in short barrels than a cartridge with a lower powder capacity due to flash and blast. 

yes it out ranges the 5.56 but after that it's attributes tend to fade. It is used because it is the only alternative in the supply system.


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## Torch (Sep 6, 2017)

Besides the weight of 7.62 rounds the Scar 17 is actually a very soft shooting rifle....


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## Token (Sep 6, 2017)

Shortround6 said:


> The term "Designated Marksmen" may be new but any outfit that had seen much combat probably had a few natural leaders (regardless of actual rank) or "go to " guys the officers relied on. Trouble in green outfits was the officers didn't know which troops to trust and the troops didn't know which officers/non-coms to trust.
> 
> Performance on the range is not a guarantee of performance in combat except in the negative. Troops that can't shoot on the range will NOT miraculously become good shots in combat. Someone who posts good scores on the range may or may not freeze in combat or otherwise perform sub par.




Yeah, but in a Designated Marksmen we are not necessarily talking about leaders, we are talking about designated riflemen at the squad level who take deliberate aimed fire even when the rest of the unit is laying down suppressing fire. To the point they are sometimes equipped with rifles that are not full auto capable.


Naturally, some of the attributes that will make a good Designated Marksmen will also be attributes that cause him/her to rise to the top of a unit in combat, so they well may be leaders within the unit, regardless of rank.


But the equipment portion was actually what I was talking about, in particular to your comment about over and under buying. The Designated Marksmen often requires different equipment to be most effective.


With regards to freezing or not, I think training has reduced that propensity quite a bit in many major military’s today. For example, more realistic, stress centered, training, vs simple range days. Training techniques that used to be only the realm of elite units are more often used at the average unit level today. Of course, there is still a long way to go in this aspect.


T!


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## soulezoo (Sep 6, 2017)

The genesis of this change (what's old is new again) has to do with the concept of "overreach" on the battlefield. Basically put, the weapons of the enemy has a greater reach or lethality range than our weapons do. For instance, we use for a squad automatic weapon a M249 in 5.56 mm. The enemy, basically using Russian weapons use a PKM firing the 7.62 x 54R has a much greater range. Now we can counter with the M240 in 7.62 x 51, but we don't use that in the same numbers they do the PKM.

SR6 already hit on a few salient points, but allow me to add a few more.

First, we are always fighting the last war... the discussions here have even bordered on that and the opinions reflect it. Politics and logistics prevent us from getting what is really needed. IMO, the cartridges needed exist and the rifles exist. The need to marry the two and then procure is what holds us back.

The SCAR is a fine weapon and an evolutionary leap from the FAL and the G3. It is in use in some Spec Ops today. It is a heavy beast though and troops of today (don't forget women) have a hard time carrying all that crap around. I'll tell you, after 25-30 lbs of body armor, another 25lbs of gear then 10-11lbs of rifle with associated ammo, I got damned tired at the end of the day and I'm not a small guy. Heavier guns and ammo is not a blessing! Ounces make pounds and pounds make pain! (Full disclosure, I have a FAL, a number of M-4's, HK91, and significant trigger time behind the SCAR 17)

Item of note: Russia has mostly abandoned the 7.62x39 and its troops use an AK-74 variant for the most part firing a 5.45mm projectile.
I made note of some of the accuracy questions. That accuracy has as much to do with the projectile and ammo as it does the rifle. An AK-47 is notoriously inaccurate due to poor ammo and the nature of the rifle itself and loose tolerances. An M-4 with a good match barrel can shoot Mk 262 ammo sub MOA all day long. Feed it some M855 and the groups open up to 2-2.5" at 100 yards. That's the best that projectile will do. (Steel core projectile designed to penetrate Soviet helmets at a given distance).

The HK 416, 417 while fine weapons are not the be all end all. Short stroke piston weapons have a different recoil feel to them that somewhat degrades accuracy for precision shooting. But it improves upon weapon fouling and does not heat up the bolt and receiver the way DI does.

Any of these battlefield cartridges from 7.62 x 54R on down suffer significant lethality degradation at range. The bullet will get there but not a lot of ass behind it when it does get there (600+ meters). Enough to wound certainly. Perhaps not enough penetration to kill though unless a fortuitous placement is made. Closer in, dead is dead. I've seen 5.56 M193 rounds literally rip a guys leg off at 50 yards. I've seen the same simply punch a couple of very small through and through holes and the victim barely knew he was shot at 200 yards.

Any cartridge adopted will be a compromise of one thing or another. Weight vs power vs recoil vs range and etc.

For an intermediate cartridge that will fit in current weapons, I kind of like where the 6.5 Grendel was going. I'd like to see just a little bigger case for about 2-300 fps faster. But even as is, it is a 1000 yard round in a 22" barrel. And does not recoil much more than 5.56. Weight is somewhere between 5.56 and 7.62.

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## Shortround6 (Sep 6, 2017)

Disclosure, the forum name is from a short 6.5mm round I had built a number of years ago. The Rem Benchrest case. Roughly a .308 with a 1/2in taken out of the body and 30 degree shoulder.
Too short and fat to make a good automatic weapons cartridge but the powder capacity is pretty much close to what is needed. 
30.5 grains of 4895 (hardly an esoteric powder) gave about 2600fps to a Serria 120 Matchking from a 26in barrel. 
which pretty much matched the ballistics of a 7.62 X 51 firing a 168-172 grain bullet. 

Perhaps it could be loaded hotter, I have no idea. It shot good (scary actually) and I had the 6.5 X 308 (full length ) for long range (over 300yds) . Either 2900+ fps with the 120 grain bullet or 2600-2700fps with a 140 from the larger case without pushing things. 
The 140 grain bullet would pretty much match a 190 grain .30 cal match bullet. 

I didn't really try the really pointy 107, 123 and 142 grain bullets. The short round had a 1 in 10 twist barrel and wouldn't shoot 140 grain bullets with the powder charge I tried. Perhaps loaded hotter with a different powder? 
Long case gun used a 1 in 9 twist and 140s stayed stabilized at 1000 yds the only time I tried that range. 

6.5 ammo is going be quite a bit heavier than 5.56 but lighter than 7.62 but has about zero chance of being adopted due to stock piles of exiting ammo and NATO standardization.

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## DerAdlerIstGelandet (Sep 6, 2017)

I personally found the 5.56 easy to learn and shoot with. It may not be the best combat rifle today, but the M-16 and it's variants are easy to give to a young kid off the block who has never fired a rifle and quickly turn them into a marksman. It has very little recoil, and reliable. Easy to take apart, clean and maintain. Easy to clear jams, and light weight.

I still enjoy shooting the weapon, and own a 5.56 mm AR-15 in the M-4 Carbine variation with a red dot/night vision scope/sight. Easy and fun to shoot. Accurate and very, very little recoil.

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## The Basket (Sep 6, 2017)

If the American do go 7.62 then does NATO go 7.62?


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## parsifal (Sep 7, 2017)

This article might be useful, though I haven't read it properly

7.62 mm Versus 5.56 mm - Does NATO Really Need Two Standard


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## soulezoo (Sep 7, 2017)

That is an issue paper from the 80's. It is interesting to note that while projectile improvements to the 5.56 is touted as making the round more effective (to be fair, this article is supportive of 7.62 and dismissive of 5.56), none have thought to make the same improvements to the 7.62 projectile.

IMO, the SS109 62 grain steel core bullet is a lousy projectile that does nothing well. Except maybe to penetrate Soviet helmets at 1000 yards. That's if one can come any where close to where one is aiming.

US Special Forces played with the 6.8 SPC for awhile. This cartridge was developed to improve lethality at closer ranges. Experience in the CQB environment exposed the limitations of 5.56 and led to this change. The 6.8 worked well under 200 meters. However, lower muzzle velocity meant that effectively the 6.8 was done around 400-500 meters tops.


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## Shortround6 (Sep 7, 2017)

It wasn't just the velocity, although that was part of it. 

The problem was trying to use standard 5.56 length magazines (easy conversion of old rifles, new barrel, new bolt and new magazine fitting in old magazine well) which mean that they had to use a short bullet of not very good ballistic shape to keep the overall length down without shoving the bullet back into the case and cutting down on powder space which would have further affected the velocity. 
A longer bullet of similar weight (more pointy on both ends) and just a tad more powder space would have offered a lot more range but would not have fit the exiting rifles for refit.

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## The Basket (Sep 8, 2017)

Fighting the last war is problematic as you could learn the wrong lesson.
Siege of Plevna? Still relevant today even if that battle was 1877! Long range gun for long range. Short range gun for short range. Simples.
The main issues are body armour and fighting insurgents who have suicide vests and the rifle that is needed in this war.
A modular weapon where you can change the barrel and the calibre would make sense.


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## Reegor (Sep 10, 2017)

I recommend the following book to anyone interested in this thread. It traces both the hardware (the standard infantry rifle of each period, for example) and the doctrines that went with them. One of the author's arguments is that there has always been a tension between the "accuracy" doctrine and the "firepower" (saturate the enemy with poorly aimed rounds) doctrine. According to him, the firepower doctrine tended to win consistently in the US military. 
He discusses issues like caliber, value of smokeless powder, etc. at length. I think the book ends before electronic sights became common. 
Enjoy! This is _way_ outside my own area, but I wrote a book on firearms manufacturing from 1800 to 1980, and this was part of my research for the book.


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## Clave (Sep 11, 2017)

If you want to kill people a long way away, bring back the Lee-Enfield .303

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## Clayton Magnet (Sep 11, 2017)

Shortround6 said:


> The problem was trying to use standard 5.56 length magazines (easy conversion of old rifles, new barrel, new bolt and new magazine fitting in old magazine well) which mean that they had to use a short bullet of not very good ballistic shape to keep the overall length down without shoving the bullet back into the case and cutting down on powder space which would have further affected the velocity.



Hence the creation of the .300 Blackout. fires a 7.62mm projectile from a 5.56mm case, uses the same magazines and bolts as the 5.56 NATO, just requires a new barrel.


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## Shortround6 (Sep 13, 2017)

Could have the same problem, either a short poorly shaped projectile to preserve powder space or a long streamline bullet that is deeply seated and doesn't really have enough powder space to do the job?


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## soulezoo (Sep 13, 2017)

The Blackout is good for one thing and one thing only. Subsonic suppressed shots at short distances. Anything else, and the round is outclassed by dozens of other cartridges and rendered nearly meaningless save for the aforementioned ability to only have to swap a barrel to use.


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## Shortround6 (Sep 13, 2017)

It seems to have the same (or roughly) ballistic capability (or potential) as the 7.62 X 39 so while we may argue about that capability it is rather obvious that it will never be a dual role cartridge (close in infantry rifle/carbine and support/armoured fighting vehicle machine gun)


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## Clayton Magnet (Sep 14, 2017)

I suppose then perhaps the US shouldn't have been so dismissive of the .280 British adoption. If the US does abandon the 5.56 (Doubt it, at least in the next few decades) I for one will do my part, and gladly take a few crates of surplussed ammo to feed my AR. Assuming of course, that Canada's present government does not reclassify it as prohibited, but that is an argument for a different thread.


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## DerAdlerIstGelandet (Sep 14, 2017)

Clayton Magnet said:


> I suppose then perhaps the US shouldn't have been so dismissive of the .280 British adoption. If the US does abandon the 5.56 (Doubt it, at least in the next few decades) I for one will do my part, and gladly take a few crates of surplussed ammo to feed my AR. Assuming of course, that Canada's present government does not reclassify it as prohibited, but that is an argument for a different *forum*.



Fixed for accuracy.


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## The Basket (Sep 21, 2017)

It said to be cancelled for the time being.
Which is right.
Seems very odd specifications.
It must be bigger than 5.56.... because bigger is better.


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## Shortround6 (Sep 21, 2017)

The Basket said:


> It must be bigger than 5.56.... because bigger is better.



depends what you are trying to do.
It also depends on physics. 
Bullets are only partially scale-able, You cannot scale down the jacket thickness in proportion to the diameter so small diameter bullets have a greater proportion of the diameter (and weight) taken up by jacket material. This means long, very long, skinny bullets to get a decent weight for high ballistic co-efficient. Which means a very quick twist barrel. It also means a longer over all length cartridge unless you seat the bullet deeply into the case which cuts into the powder capacity. 
Optimum bullet diameter for good shape (long range) and light bullets (relatively) is around .264 to .284 although the 7mm/.284 is bordering on the bullets not being enough light than the 7.62/.308 to show a significant difference in weight. 

With steel (green) cores the weight situation gets worse as even long bullets don'r have the weight per unit of frontal area.

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## Glider (Sep 21, 2017)

The big missed oppertunity was not going to the .280 round as designed for the EM2. Its power lies between the 5.56 and the 7.62 and would ahve been a good fit for todays situations


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## Shortround6 (Sep 21, 2017)

It would have. I knew a man who worked at Aberdeen proving ground at the time in question and the 7mm caliber impressed him enough to build several 7mm rifles in wildcat chamberings like 7mm/30-30 inmid/late 50s and early 60s.


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## The Basket (Sep 22, 2017)

6.5mm Swede is said to be the best of the bullets.


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## Shortround6 (Sep 22, 2017)

Using which bullet?
Hate to be so technically correct but the "6.5mm Swede" is a cartridge that can be loaded with a variety of "bullets".
I do own a 6.5 Swedish Mauser in addition to my 6.5mm X 308 on a Winchester 70 action and a 6.5 Rem BR on a Remington action.
I also have a 6.5mm Remington magnum on a Remington 40 X single shot action. Only the Mauser has a factory barrel (barrel made by same company that built the action)

All will use a variety of 6.5mm bullets. Some better than others.
The 6.5 Swedish Mauser was originally loaded with a 156 grain round nose bullet but this was replaced by a 139 grain spitzer.
There are several dozen different commercially available bullets in 6.5mm caliber for a variety of uses, mostly sporting (hunting and target shooting) but few, if any, military bullets (AP, tracer, etc)

BTW I have nothing against the 6.5mm Swedish as a cartridge. I went with the 6.5 X 308 at the time ( early 90s) because in the US it was cheaper and easier to get 243 brass and expand the necks than it was to get 6.5 X 55 Swedish brass in the quantities I needed (hundreds of cases).


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## Token (Sep 22, 2017)

soulezoo said:


> The Blackout is good for one thing and one thing only. Subsonic suppressed shots at short distances. Anything else, and the round is outclassed by dozens of other cartridges and rendered nearly meaningless save for the aforementioned ability to only have to swap a barrel to use.



On the other hand I really like .458 SOCOM, with 500 or 600 grain subsonics, in this application. With a suppressor it makes a heck of a nice night time pig gun.

T!


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