Section Infantry Weapons

[Little J]

Yes I was, sorry I should have been more clear... In a previous post you said 2030, that's a little over 6 years away. You implied that we should just go with the 6.8, an unproven, experimental round.

Could you expand on your second point, as I'm not sure what point you're trying to make.

[RunningStrong]

Do you want your designated marksman to actually hit something or just miss it by a smaller margin? Breaking down link will ensure the later.

Then why compromise with 6.5CM? Give them .338 the best they can get.

Missing by a smaller margin is called suppressing fire, and it's often an acceptable outcome at significant ranges.

I understand the emergency argument but you could say the same about 338lapua.

The current deployment of .338 is not at a section level.

It’s a great choice but it’s the 7.62x51 that now needs to be phased out in the GPMG, ideally to be replaced by 300Norma.

Why would you want three rifle calibres in your section? That's a nightmare for logistics let alone the practicalities of operating in a section.

Worth bringing the Minimi back for 6.5CM especially if the GPMG moved up to 300Norma.

I'm sure something from FN will come through.

[Andy-M]

It already has, this is from 2019

https://www.thefirearmblog.com/blog/201 ... creedmoor/

[Poiuytrewq]

Then why compromise with 6.5CM? Give them .338 the best they can get.

Totally different ball game.

Missing by a smaller margin is called suppressing fire, and it's often an acceptable outcome at significant ranges.

Suppressing fire is best provided by the minimi and GPMG. The designated marksman is providing harassing fire and neutralising threats. If the 5.56 was replaced by a more capable 6.5 round the designated marksman role would be obsolete overnight.

Why would you want three rifle calibres in your section? That's a nightmare for logistics let alone the practicalities of operating in a section.

6.5x47 plus 338Norma is all that’s needed.

I'm sure something from FN will come through.

If the GPMG stays at 7.62x51 then it isn’t needed. If the GPMG jumped up to 338Norma then a 6.5CM minimi might be worth a look.

[mrclark303]

Yes I was, sorry I should have been more clear... In a previous post you said 2030, that's a little over 6 years away. You implied that we should just go with the 6.8, an unproven, experimental round.

Could you expand on your second point, as I'm not sure what point you're trying to make.

Morning Little J, first off, 6.8 x 51mm is no longer experimental, it's in production and selected by NATO's main partner and the proverbial founder of the feast.

So pushing forward from here, the choice will be 6.8mm with 5.56mm as the secondary calibre.

I'm genuinely at a loss to understand why the military would adopt a non standard 6.5 Creedmoor firearm as a limited issue piece, it's so close in performance to 7.62 NATO, I really don't see the point. As said, it's not a NATO standard calibre and will require its own logistics system, outside of NSN's.

I would love to hear the logic behind that decision.

It's fine (I suppose) when seen in the context of limited SF use.

6.8mm is an extremely high pressure round that will increase effective range over 7.62 NATO and is apparently able to defeat all current body armour. Coupled with the sophisticated optics and a typical infantry section will be able to provide far more targeted and subsequently lethal fire.

The downside is the full high pressure service version, that will require specialist tooling to manufacture and a raft of new rifles developed (or re-engineerd older designs) to withstand the very high pressure.

It's interesting, I dare say many NATO countries will just stick to 5.56mm.

[RunningStrong]

Totally different ball game.

Nope. Still a bullet.

Suppressing fire is best provided by the minimi and GPMG. The designated marksman is providing harassing fire and neutralising threats. If the 5.56 was replaced by a more capable 6.5 round the designated marksman role would be obsolete overnight.

But obviously it's not being replaced by 6.5 is it? That's painfully obvious that the Rangers/RM aren't using 6.5, neither are the US. In fact, who is using 6.5 in infantry rifle, anyone?

6.5x47 plus 338Norma is all that’s needed.

If the GPMG stays at 7.62x51 then it isn’t needed. If the GPMG jumped up to 338Norma then a 6.5CM minimi might be worth a look.

Aren't you already suggesting that 6.5 becomes an infantry rifle round as well, so why have a 6.5 minimi too? Surely the point of the section MG is to hit and suppress targets further than the collective fire of the section?

[Little J]

Morning Little J, first off, 6.8 x 51mm is no longer experimental, it's in production and selected by NATO's main partner and the proverbial founder of the feast.

So pushing forward from here, the choice will be 6.8mm with 5.56mm as the secondary calibre.

I'm genuinely at a loss to understand why the military would adopt a non standard 6.5 Creedmoor firearm as a limited issue piece, it's so close in performance to 7.62 NATO, I really don't see the point. As said, it's not a NATO standard calibre and will require its own logistics system, outside of NSN's.

I would love to hear the logic behind that decision.

It's fine (I suppose) when seen in the context of limited SF use.

The logic for the choice of the 6.5mm Creedmoor

The new 6.8mm is not as yet in full production, the US Army has plans to break ground later this year at the Lake City Army Ammunition Plant for a new facility to initially produce the 6.8mm cartridges, it will be expensive to manufacture in the many tens of millions required compared to the standard brass cased rounds that has been used for the last hundred odd years e.g. 303, 7.62, 6.5CM, 5.56 etc. The new 6.8mm case is required to take such high pressures never attempted before for an infantry round, higher than the Lapua 338 magnum, result the 6.8mm case needs a stainless steel head, locking washer and brass body.

To be noted that Lake City Army Ammunition Plant are in production of a downloaded 6.8mm with a standard brass case, US Army classifies it as a training round.

As noted in my post yesterday the XM7 and XM250 using the 6.8mm are having problems under testing with fume extraction and accuracy and not surprised in the least as they are pushing the boundaries so far. As said the full powered round will be expensive and it appears the US Army will not use it for training, but instead the standard downloaded LC brass cased round for training as expect if they did use the full powered round in the XM7 and XM250 for training it will drastically shorten their lives, which might only be acceptable in a war.

Possible the full powered 6.8mm will be so limited in take up that it will have a short life, so understand why the Marines chose the 6.5mm Creedmoor for their limited number of semi-auto sniper rifles which give better accuracy and range than the 7.62, will only need a change barrel of the L129 to fire it, expect the 6.5CM dimensions so similar to the 7.62 it will be able to use the same magazine. The 6.8mm with its extreme high pressures would put the L129 under more stress than the rifle was designed for and burn out the barrel at a much faster pace.

[Poiuytrewq]

Nope. Still a bullet.

They aren’t even nearly comparable. The rifles are totally different. The ballistics are completely different. The training requirements due to the recoil are totally different and the rate of fire is totally different. To operate a 338lapua to its full potential it requires two operators.

Different ballgame.

But obviously it's not being replaced by 6.5 is it? That's painfully obvious that the Rangers/RM aren't using 6.5, neither are the US. In fact, who is using 6.5 in infantry rifle, anyone?

The 6.8x51 at those pressures is a complete dead end. It will cause no end of trouble.

There are better options out there. The 6.5mm projectile is ballistically superior to both the 6.8 and 7.62. Start from there.

The 6.5x47mm is the ballistic sweet spot. It has acceptable pressure, acceptable weight of ammo and fantastic ballistic performance with moderate recoil.

If sense prevails the new NATO round will end up somewhere around the 6.5x47mm.

The 338Norma is the perfect step up to bridge the gap between 7.62x51 and .50

6.5x47 and 338Norma. That’s all that’s needed.

Aren't you already suggesting that 6.5 becomes an infantry rifle round as well, so why have a 6.5 minimi too? Surely the point of the section MG is to hit and suppress targets further than the collective fire of the section?

Just my opinion but as the round increases in case capacity, sustained fire with mod fitted rifles will become more difficult. Less of a problem with 5.56 than 6.5x47. If the minimi hasn’t got a mod that allows sustained fire to suppress targets without overheating the mod.

As the recoil increases in the standard infantry weapon the rate of fire from each section will decrease or accuracy will suffer. The minimi helps re-establish the correct rate of fire for effective suppression at the sectional level. It’s worth considering that the designated marksman would no longer be needed so it could be a straight swap for the minimi and still retain the GPMG.

The 6.5x47mm can handle anything up to 300-400m even in high wind and well beyond in low wind conditions. The 338Norma GPMG can defeat body armour and destroy light vehicles well beyond 600m. It’s the perfect mix, much better than 5.56/6.5CM/7.62x51

Clearly you have a different view.

[Poiuytrewq]

…6.5mm Creedmoor for their limited number of semi-auto sniper rifles which give better accuracy and range than the 7.62…

I agree with the most of what you have written apart from this part.

The 6.5CM will not necessarily give better accuracy. Accuracy is dependent on many variables but if those variables are all identical only then can the two rounds be directly compared. Effectively this means rifle, optic, operator training/experience and quality of ammo.

The 6.5CM has a projectile that has a higher BC than an equivalent 7.62 projectile. Therefore if the velocities are identical the higher BC projectile should drift less in the wind and drop less from the point of aim at longer ranges. However a highly trained operator will negate the difference between the two calibres.

As the 6.5CM case capacity is less than the 7.62x51 and the bullet weight is lighter the amount of felt recoil is reduced. Felt recoil is another one of those variables that affect accuracy.

Although it cannot be categorically stated that the 6.5CM is more accurate than the 7.62x51 due to the factors listed above it is easier to achieve the desired results for a less experienced operator.

[NickC]

…6.5mm Creedmoor for their limited number of semi-auto sniper rifles which give better accuracy and range than the 7.62…

I agree with the most of what you have written apart from this part.

The 6.5CM will not necessarily give better accuracy. Accuracy is dependent on many variables but if those variables are all identical only then can the two rounds be directly compared. Effectively this means rifle, optic, operator training/experience and quality of ammo.

The 6.5CM has a projectile that has a higher BC than an equivalent 7.62 projectile. Therefore if the velocities are identical the higher BC projectile should drift less in the wind and drop less from the point of aim at longer ranges. However a highly trained operator will negate the difference between the two calibres.

As the 6.5CM case capacity is less than the 7.62x51 and the bullet weight is lighter the amount of felt recoil is reduced. Felt recoil is another one of those variables that affect accuracy.

Although it cannot be categorically stated that the 6.5CM is more accurate than the 7.62x51 due to the factors listed above it is easier to achieve the desired results for a less experienced operator.

My ref for making the above comment was based on the USSOCOM trials reported by Wikipedia on its 6.5mm Creedmoor page

Military use
In October 2017, U.S. Special Operations Command (USSOCOM) tested the performance of 7.62×51mm NATO (M118LR long-range 7.62×51mm NATO load), .260 Remington, and 6.5mm Creedmoor cartridges out of SR-25, M110A1, and Mk 20 Sniper Support Rifle (SSR) rifles. SOCOM determined 6.5 Creedmoor performed the best, doubling hit-probability at 1,000 m (1,094 yd), increasing effective range by nearly half, reducing wind drift by a third, with less recoil than 7.62×51mm NATO rounds.

[Poiuytrewq]

Thank you.

Very interesting results.

Hit probability isn’t technically the same as accuracy but if the wind drift and recoil is reduced it will absolutely improve hit probability.

…increasing effective range by nearly half…

This seems like the most unbelievable statement as the rounds are ballistically pretty similar.

Hope RM didn’t make the decision based on that.

[NickC]

Thank you.

Very interesting results.

Hit probability isn’t technically the same as accuracy but if the wind drift and recoil is reduced it will absolutely improve hit probability.

…increasing effective range by nearly half…

This seems like the most unbelievable statement as the rounds are ballistically pretty similar.

Hope RM didn’t make the decision based on that.

As i do, sincerely hope the RM carried out their own trials with the 6.5CM to prove or disprove the SOCOM claims.

[mr.fred]

Hit probability isn’t technically the same as accuracy

But arguably more important.

This seems like the most unbelievable statement as the rounds are ballistically pretty similar.

Depends on how you are defining effective range. It's usually the range at which a certain hit probability floor is reached, but other definitions are available.

[RunningStrong]

They aren’t even nearly comparable. The rifles are totally different. The ballistics are completely different. The training requirements due to the recoil are totally different and the rate of fire is totally different. To operate a 338lapua to its full potential it requires two operators.

Different ballgame.

Have you shot 338? The recoil isn't going to kill you, it's quite manageable.

Albert Arms will sell you a .338 LM AR10.

Same ballgame.

The 6.8x51 at those pressures is a complete dead end. It will cause no end of trouble.

And yet it's being adopted quite widely by the USA...

[Poiuytrewq]

But arguably more important.

Depends how it’s measured.

It’s only a credible comparison if all the variables are identical. For example, were both rifle printing identical groups sizes at 100m before pushing out to 400m 800m and 1000m?

Even a tiny difference at 100m between the rifles such 1MOA vs 1.3MOA could explain the difference at longer range.

Interesting that only one bullet was tried in the 7.62x51. Not saying it’s not valid, simply that’s it’s a surprising result therefore needs treated with scepticism until the detailed data proves it.

Depends on how you are defining effective range. It's usually the range at which a certain hit probability floor is reached, but other definitions are available.

For medium calibres such 6.5CM and 7.62x51 with a 22” barrel around 600m seems fair.

A more than 30% different seems extreme.

As i do, sincerely hope the RM carried out their own trials with the 6.5CM to prove or disprove the SOCOM claims.

Its a great round but the difference in the real world doesn’t seem that stark.

[Poiuytrewq]

Have you shot 338? The recoil isn't going to kill you, it's quite manageable.

It’s not exactly a pussycat, manageable but far from ideal, especially when firing from awkward positions.

Out to 600m what are you gaining unless it’s anti-material. More weight, more recoil, more bullet drop, less accuracy. It’s not a good trade.

Self spotting hits from of a 338lapua at longer ranges in lighter rifles is very very difficult. In a 6.5CM it’s a breeze.

The L115 338lapua when used in teams is a phenomenal tool. As a calibre for a dedicated marksman rifle it’s a poor choice. The 6.5CM is a great choice.

Interesting that the Royal Marines seem to agree.

And yet it's being adopted quite widely by the USA...

Let’s wait and see how that goes.

[NickC]

The 6.8x51 at those pressures is a complete dead end. It will cause no end of trouble.

And yet it's being adopted quite widely by the USA...

it's being adopted quite widely by the USA..." Can you quote examples as have seen none other than the US Army.

The Sig Sauer XM7 and XM250 with the 6.8mm and have not passed their acceptance tests and and not been fielded, having problems with accuracy and fume extraction

If you have seen pics of a sectioned old barrel the throat it looks like a cracked dried up river bed, plus the steel is forced inwards reducing the diameter of the barrel so when bullet is fired it tears the carefully crafted jacket of the bullet which does nothing good for its accuracy. The 6.8mm with its unprecedented high pressures creating more heat especially in full auto where the problem is magnified, can be alleviated by costly expedients, e.g. in 1967 Springfield developed a stellite lined chromium plated barrel for the 5.56 but was only tested at 200 rpm, but as said 6.8mm at full auto expect will have higher temperatures input. Would not be surprised if accuracy averaging only 5 MOA at 100 metres if not more.

The XM7 is the US first service rifle specified be fitted as standard with a coke can sized suppressor on the end of barrel to reduce sound, recoil and flash, but appears from the trials to result in too much blow back of the toxic gases, another drawback of the suppressor will be additional carbon fouling of the barrel, which again will reduce accuracy.

Expect if they through enough money at the XM8 and XM250 6.8mm they may come up with an operational/reliable weapons, but looks a colossal waste of money if instead they had just chosen a standard round like the 6.5CM.

[mrclark303]

The 6.8x51 at those pressures is a complete dead end. It will cause no end of trouble.

And yet it's being adopted quite widely by the USA...

it's being adopted quite widely by the USA..." Can you quote examples as have seen none other than the US Army.

The Sig Sauer XM7 and XM250 with the 6.8mm and have not passed their acceptance tests and and not been fielded, having problems with accuracy and fume extraction

If you have seen pics of a sectioned old barrel the throat it looks like a cracked dried up river bed, plus the steel is forced inwards reducing the diameter of the barrel so when bullet is fired it tears the carefully crafted jacket of the bullet which does nothing good for its accuracy. The 6.8mm with its unprecedented high pressures creating more heat especially in full auto where the problem is magnified, can be alleviated by costly expedients, e.g. in 1967 Springfield developed a stellite lined chromium plated barrel for the 5.56 but was only tested at 200 rpm, but as said 6.8mm at full auto expect will have higher temperatures input. Would not be surprised if accuracy averaging only 5 MOA at 100 metres if not more.

The XM7 is the US first service rifle specified be fitted as standard with a coke can sized suppressor on the end of barrel to reduce sound, recoil and flash, but appears from the trials to result in too much blow back of the toxic gases, another drawback of the suppressor will be additional carbon fouling of the barrel, which again will reduce accuracy.

Expect if they through enough money at the XM8 and XM250 6.8mm they may come up with an operational/reliable weapons, but looks a colossal waste of money if instead they had just chosen a standard round like the 6.5CM.

The issue is that Creedmoor was trialed and found not to offer a real advantage over 7.62 x 51mm, as in it can be defeated by modern body armour.

6.8 has been specifically designed and created, alongside it's firearms and optics, to allow an unprecedented high degree of accurate and lethal effect at squad level. That in itself will be a game changer.

Teething problems, certainly, but every new weapons system has issues to be ironed out. The M16 was no different, it took a raft of modifications to A1 standard to get there. Chromed bore and chamber, changed buffer assemblies, modified extractor, forward assist etc, etc.....

This is no different, it's the next generational leap, it will succeed as it's a programme that's simply reached critical mass and it's now too big to fail.

As 5.56mm is carrying on as a secondary calibre and 7.62 can fill the immediate gap with a raft of AR10 derivatives (or chamberd in Creedmoor of course), to provide the ability to reach out and say hello, then there's no real pressing concern.

[Little J]

The issue is that Creedmoor was trialled and found not to offer a real advantage over 7.62 x 51mm, as in it can be defeated by modern body armour.

USSOCOM have adopted it for their Precision Rifle, RM's have adopted it for the L129, I would think that their decisions took into account modern body armour.

The projectile in the 6.8 could actually be very good, but to get the performance required from the M7's short barrel the cartridge is running at extremely high pressure and is spanking said barrels.

Other countries have shown an interest in the 6.8, because its the Americans, but how many have held off from replacing their rifles with new 6.8's instead of 5.56's? None that I am aware of.

Like I've said before, there needs to be a full, open and unbiased NATO trial for a new calibre. The last 2 have been US biased and haven't really been successful, lets try and avoid the hat-trick.

[Poiuytrewq]

Like I've said before, there needs to be a full, open and unbiased NATO trial for a new calibre. The last 2 have been US biased and haven't really been successful, lets try and avoid the hat-trick.

If penetration is the primary concern then long thin projectiles driven at high velocity is the way to achieve it but so much more could be done to the actual projectile to help achieve the required results at lower chamber pressures.

I really don’t think Euro NATO will adopt the 6.8x51 at the higher chamber pressures unless some new internal barrel coating or a new heat/wear resistant barrel steel is developed.

However even IF those barrel improvements could be made the 6.5x51 would still penetrate better than 6.8x51 at the same chamber pressure so why 6.8?

The only way to gain consensus among NATO members is to have a fair and transparent competition with all the options on the table and then let the data decide.

If so, the 6.8x51 will not win.

[mrclark303]

Like I've said before, there needs to be a full, open and unbiased NATO trial for a new calibre. The last 2 have been US biased and haven't really been successful, lets try and avoid the hat-trick.

If penetration is the primary concern then long thin projectiles driven at high velocity is the way to achieve it but so much more could be done to the actual projectile to help achieve the required results at lower chamber pressures.

I really don’t think Euro NATO will adopt the 6.8x51 at the higher chamber pressures unless some new internal barrel coating or a new heat/wear resistant barrel steel is developed.

However even IF those barrel improvements could be made the 6.5x51 would still penetrate better than 6.8x51 at the same chamber pressure so why 6.8?

The only way to gain consensus among NATO members is to have a fair and transparent competition with all the options on the table and then let the data decide.

If so, the 6.8x51 will not win.

I would agree mate, unfortunately until European nations actually pay to defend themselves, then we are all totally reliant on Uncle Sam, that includes conversations regarding all manor of NATO standards, so the founder of the feast calls the shots....

The reality is most European NATO members will simply stick to 5.56mm.

It will be interesting to see if the UK does....

[Poiuytrewq]

It will be interesting to see if the UK does....

In the end it will become logistical spaghetti so a solution will have to be found. I hope the US can make it work but it will be new tech if they can.

I don’t think it’s completely impossible that a Euro calibre could be adopted as an offshoot of PESCO or something similar. For the EU the grandstanding would be delicious.

Time will tell.

[NickC]

The issue is that Creedmoor was trialed and found not to offer a real advantage over 7.62 x 51mm, as in it can be defeated by modern body armour.

The US trials the 6.5CM vs 7.62 showed it doubling the hit probability at 1000 metres, 33% increase in effective range, 30% increase in energy on target, 40% decrease in wind effect on bullet and decreased recoil, you might not call that a real advantage but i would call that a major advance over the 7.62.

The design of 6.5 CM with its slightly shorter case allows it to fit long bullets without seating bullets deep into the body of the case so as to be able to fit within the max COAL of a AR10 rifle bringing the advantages of bullets with high ballistic coefficients and sectional density that enables less wind drift, relatively low recoil and long barrel life.

No trials were ever conducted to justify the selection the 6.8 x51 cartridge, expect some US Army Colonel made an arbitrary choice to use brute force to defeat modern body armour and never considered the other alternatives.

[NickC]

The L129A2 the RM procuring in 6.5mm Creedmoor

U.K. Royal Marines adopt a 6.5CM LMT as the L129A2, ft. HUXWRX and Leupold - The Firearm Blog

[BB85]

I didn't pick up on the Royal Marines aspect of the purchase initially. I know the RM are looking to separate themselves somewhat from the army after effectively being treated like an elite infantry regiment in Iraq and Afghanistan. Maybe that will reduce the logistics issues a bit. On the other hand will that create more of an issue as the next time a war goes hot the RM will likely find themselves in the same situation serving alongside the army.