New US Army Rifle

So guys,after 56 odd years, there is finally a replacement for the venerable M16 and it's variants in US Army service. A slow creeping replacement that is, with a brand new rifle and new calibre.

Sig's MX5 and their 6.8x51mm round will slowly roll out and replace the M4.

The MX5 appears to be a relatively 'safe' route to take, nothing overly revolutionary or risky, it's a aluminium upper and lower rifle, rotating bolt, short stroke piston design with controls that will be immediately comfortable to anyone used to an AR15.

The rifle uses both a non reciprocating side charging handle and a 'T' rear charger.

The biggest surprise is the calibre, so much for intermediate! 6.8x51 is a very powerful round by all accounts, very high pressures too...

You can bet all the major manufacturers are scrambling to design new rifles for the new calibre, possibly adaptations of AR10 designs, somewhat beefed up to take the chamber pressure of the new round.

I assume NATO will adopt the new calibre too, certainly the MX5 looks to be one hell of a piece of hard hitting kit, I would suppose the M240 'could' be re-barreled for the new calibre, if it can take the stress of the new round?

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Originally Posted by mrclark303

I assume NATO will adopt the new calibre too

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I'll bet we don't. Not for 20-30 years.

It's interesting Jim, funny old world, we go from fully fledged battle rifles, to the intermediate cartridge and turn full circle back to battle rifles!

I guess America drums the beat in NATO and we all slowly fall behind and get into step... It's fair enough, they spend enough money to guarantee and effectively underwrite the rest of NATO's security after all.

I would hope the UK just buys the rifle off the shelf from Uncle Sam and converts to the new calibre as it becomes widely available.

It appears Sig have won the whole shooting match in the US, from new service pistol, to new rifle and LMG and designed the new 6.8 round too!

So the wheel has come full circle in the past 70 years! The British-designed .280/30 cartridge was rejected in favour of the 7.62x51, which in turn was replaced by the 5.56x45 (which went through a number of modifications) and we now have a composite (read expensive) cased 6.8x51 that is about 15% better than the original .280/30 but at a 40% increase in operating pressure. Why not just use a steel-cased 7/08 at about 65,000 PSI (or a similar sized 6.8 that will not fit lower pressure sporting rifles), essentially the same result at a greatly reduced expense. How much public money has been squandered on this bumbling mismanagement over the last century?

I always like the 7x49 developed for Venezuela and sold to them in the early FAL rifle which I believe was 30K in that order. Later on even Castro had one !

The Belgium FN factory took the American 7,62x49 case and necked it down to use the 7mm S12 bullet and you have the 7x49.15mm Liviano cartridge

photos: 7x49, 7,92x40 and 280/30 single photo is 7x49mmAttachment 125674Attachment 125673

They say a military goes into war well prepared for the war that came before it.

A more powerful, longer range cartridge would do well in the Middle East.

Hopefully there won’t be a next large scale war to figure out if this was the right choice.

I think the idea of the very high pressure 6.8 x 51mm round is to allow it to perform well in a 13" barrel of the MX5.

It makes you wonder if it's a limitation of the round, imagine the pressure generated if it was fired through a 21" inch barrel!

It's hard to see it having a civilian application too...

A few further observations on the MX5, it apparently has two gas settings, normal and " make it work" even its jammed with mud...

It somewhat surprisingly got a forward assist and one interesting feature are replacement sacriffical structural points, designed to do the 'stretching' instead of the upper receiver..... Interesting idea...

Seems the Brits had it right when they went the 7mm way before WWI and after WWII. The new cartridge looks like it could be the 7mm-08.

Strange that those who should know better, who are highly qualified in their respective technical armaments rolls, always make hard work on selecting the right calibre. I am sure there are those on this site that will remember days gone by when weapons were built (as they should be) around the round to be used NOT the other way round.
Interesting times. The 7.62 x 51 was designed to stop a man in his tracks, these days they seem to be satisfied with the softer, feather approach......................... "Lets not hurt them".

I think I had better start drinking whatever they are having:madsmile:

I certainly wouldn't want to get hit by Sig's new 6.8 round Gil, it packs one hell of a wallop, designed to defeat modern body armour, so that tells you it doesn't play nicely with others mate!!

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Originally Posted by mrclark303

I certainly wouldn't want to get hit by Sig's new 6.8 round

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Have they designed it so that the round "tumbles" through the body rather than pass straight through? If that is the case it will do a lot of damage to anyone unfortunate enough to be on the receiving end.

Please excuse me if I'm not overawed by a 'gasp', 'new' military cartridge. Paging through 'Cartridges of the World' you will probably find similar cartridges either in production or was in production or was developed, etc. Ditto for 'new' bullets and composite cases. What is worth keeping in mind is the military move away from miniature cartridges, to one between those from WWI/WWII use and the miniature ones. This move has slowly gained momentum in the last two decades.
Don't be surprised when similar ones 'suddenly' appear in many other countries.

I imagine the XM5 and XM250 SAW will go to the special operations folks first then the rapid deployment forces. Then other forces like regular Army, Army Reserve and National Guard folks later. The 5.56mm NATO cartridge has been developed to to fullest and is lacking in punching through the latest body armor at distance. As the 6.8x54mm/.277 Fury cartridge continues to get fielded other special ops folks in other parts of the world will adopt it as well. The Army has already looking to convert the M240 and Mini-gun to that caliber. My understanding is the round will have a chamber pressure of 80,000 psi and a muzzle velocity of over 3,000 fps out of a 13 inch barrel. SIG Sauer is already advertising a civilian version called the MCX-Spear with a MSRP of 7,999.00 US dollars. I for one will not be rushing out to order one. LOL I maybe later get a good bolt action chambered in the .277 Fury just to play with.

The high chamber pressure and velocity tells me the cartridge is quietly going to be downloaded in its life. Sooner or later, probably sooner than later. But I've been wrong before.

The Pedersen 276 cartridge was designed for military semi auto rifles many years before we saw the 7,62x51mm NATO cartridge. with new power loadings it would still make a good choice in the AR15/M16 firearm today. Note the nice taper to the cartridge case which is ideal for feeding. It gave way to the 30-06 actually 30M1 cartridge in the 1930's and died,

photo; 7,62x51 NATO and 276 PedersenAttachment 125716

Yeah, been hearing the chatter around the campus on this rifle. They have put in the 2023 budget for 29000 +/- new rifles I didn't hear how many will be the MX5 and how many will be the SAW replacement.

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Originally Posted by Flying10uk

Have they designed it so that the round "tumbles" through the body rather than pass straight through? If that is the case it will do a lot of damage to anyone unfortunate enough to be on the receiving end.

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I think that's more an issue with a small calibre intermediate round F10, in order to offset the small calibre with stopped power.

I think 6.8x 51 mm will hit like a freight train, it packs high velocity and a reasonable bullet size to retain energy downrange.

If you get the chance to compare calibers
(tracer) side by side, it makes for a fascinating exercise, you can see the obvious limitations of 5.56mm, once over 300 yards it's adversely affected by cross winds ... If it's really blustery wind shear, forget it, you won't hit a bloody thing.

Compare it to .30-06 or 7.62x51, that just heads downrange and hits the target accurately at far greater ranges..

The Boers and the Spaniards created quite a bit of consternation in their opponents with the 7x57 Mauser at the tail end of the nineteenth century. The British went to far as to develop the P13 rifle and its .276 Enfield ammunition in response. When Teddy Roosevelt was being briefed on the replacement for the Krag he reportedly asked General Crozier, "Why not just buy the Mauser?" Seems like the new whiz bang cartridge will fall in somewhere between the 6.5 Swede and the 7 Mauser in performance, albeit in a shorter case. What goes around, comes around.

Waste of time and money for the US military. Rifles will burn out very quickly (I have heard around 1000-2000rd barrel life), and the troops can't even shoot good enough to take advantage of the range benefits of the rounds. When your troops hit a target at 300m 50% of the time in peace, and a target 100m away 50% of the time in combat, why are you trying to field a weapon which has a effective range of 1200m? And that is also with a rifle which has significantly less recoil so expect the accuracy results to drop even more with the new rifle.

True. The Brits had the same challenge with the 276 cartridge.

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Originally Posted by fjruple

a chamber pressure of 80,000 psi and a muzzle velocity of over 3,000 fps out of a 13 inch barrel

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If thats the case then if the US forces adopt the round that had better get a shite load of replacement barrels, I own a 6.5 x 284 running 140gn Bergers at around 2850fps and @60,000 psi chamber pressure my throats are usually shot out around the 6-700 round count with the muzzle not much better usually results in a 2" lop off at the chamber and 1" at the muzzle.
3000fps and 80,000psi heck after 1 sortie with a minigun you'll be in for 6 new barrels!

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Originally Posted by CINDERS

If thats the case then if the US forces adopt the round that had better get a shite load of replacement barrels, I own a 6.5 x 284 running 140gn Bergers at around 2850fps and @60,000 psi chamber pressure my throats are usually shot out around the 6-700 round count with the muzzle not much better usually results in a 2" lop off at the chamber and 1" at the muzzle.
3000fps and 80,000psi heck after 1 sortie with a minigun you'll be in for 6 new barrels!

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Cinders--

I unfortunately do not know what material SIG Sauer is planning to use for the barrels but it must be pretty tough to standard up to the projected pressures and speed. I am thinking probably something like a Stellite liner and such. We will see how quietly the XM5 and XM250 disappears if the performance is not there.

What if the UK decides to adopt the new ammunition but not the rifle? How easy will it be for the UK to get it's SA80's converted? One can envisage the UK taking this sort of approach to "save money" and then end up spending twice as much than it would have done if it had purchased the new rifle straight away.

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Originally Posted by Flying10uk

One can envisage the UK taking this sort of approach to "save money" and then end up spending twice as much than it would have done if it had purchased the new rifle straight away.

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It's not just them, that's how it ends up. New material on an old coat until no old material remains. Then scrap and buy new.

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Originally Posted by Flying10uk

What if the UK decides to adopt the new ammunition but not the rifle? How easy will it be for the UK to get it's SA80's converted? One can envisage the UK taking this sort of approach to "save money" and then end up spending twice as much than it would have done if it had purchased the new rifle straight away.

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Morning F10, it's basically not possible, pressure issues aside, it's the same length as 7.62mm i.e 51mm, so beyond the physical dimensions of the magazine well.

The only route would be to wait and see what HK Colt etc come up with, my guess would be a derivative of the AR10, beefed up to take the considerable additional pressure.

The UK is currently playing a waiting game, with the A3 rebuild of the L85 and limited issue of the Colt Canada C3.

You can guarantee that now 6.8x 51mm has been selected, all the main manufacturers are scrambling to come up with their own designs.

I don't think very many of the current military rifles can be converted to the 6.8x51mm cartridge. First the cartridge is the about the size of the 7.62mm NATO round, which makes any 5.56mm NATO size rifle out of the question. Second if a 7.62mm NATO type rifle is used its design will have to take the pressures of 6.8x51mm cartridge.

The Army appears to be headed for a two-tier system for the near future, at least, according to an article in the Army Times.

"The weapon is designed and aimed at close combat forces. That includes infantrymen but also cavalry scouts, combat engineers, forward observers and combat medics, said Brig. Gen. Larry Q. Burris, Jr. director of the Cross-Functional Team-Soldier Lethality and Infantry School Commandant...There are no current plans to issue the NGSW to non-close combat soldiers. Soldiers in fields other than those listed or not assigned to a direct combat unit will continue to use the M4 options and the M249 SAW, Burris said."

REMFs and Fobbits will continue to carry the M4. Supply sergeants will be saddled with the burden of three types of ammo? Will belt fed guns on vehicles remain 7.62x51? Will belt fed guns disappear from the squad/platoon level?

I thought the doctrine of old as with the 5.56 round it was for controllable fire by the weapons user more accurate fire and less being belted around from say dumping a 20 round mag from a M-14 in 308.
With regards to the 6.5 there will be a substantial bang probably not as much recoil as a 308 but being able to control the POA under high cyclic rates of fire whether full auto or semi will need to be seen I know my 6.5 makes a hefty report and thats with a 30" barrel a 13" barrel well you wont want to be close together!
Reminds me of the Germans in WWII with the Kurtz round looking for an alternate round for the troops so accurate fire in a semi auto can be applied.

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Originally Posted by old tanker

REMFs and Fobbits will continue to carry the M4. Supply sergeants will be saddled with the burden of three types of ammo? Will belt fed guns on vehicles remain 7.62x51? Will belt fed guns disappear from the squad/platoon level?

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Five types if you include 9mm ammo for pistols as well as .50 cal....and maybe six if including .338 for sniper use?

Beats even WW2 which had four with .45ACP, .30 cal carbine, 30-06 and .50 cal.

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Originally Posted by CINDERS

I thought the doctrine of old as with the 5.56 round it was for controllable fire by the weapons user more accurate fire and less being belted around from say dumping a 20 round mag from a M-14 in 308.
With regards to the 6.5 there will be a substantial bang probably not as much recoil as a 308 but being able to control the POA under high cyclic rates of fire whether full auto or semi will need to be seen I know my 6.5 makes a hefty report and thats with a 30" barrel a 13" barrel well you wont want to be close together!
Reminds me of the Germans in WWII with the Kurtz round looking for an alternate round for the troops so accurate fire in a semi auto can be applied.

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Hi Ron, the plan is for the MX5 to be permanently fitted with a moderator, to reduce recoil and blast, that 13" barrel without would produce a three foot flame I should think!

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Originally Posted by GeeRam

...Beats even WW2 which had four with .45ACP, .30 cal carbine, 30-06 and .50 cal.

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You forgot .38 Special in Navy aviation revolvers, .32 ACP and .380 in General Officer issue pistols.