When 6.8x51mm brass hits the fan

6.5 supermanbunn,

I've been thinking it might make a good '.270 Short'. Should prove to be an interesting cartridge to play wit, at any rate.

I want to neck it up to 45 cal and make 45 Fury-Raptor. Kills on one end maims on the other.

Assuming Sig managed to loose the the X on the XM-5 and XM-250 it will be interesting to see how this case technology migrates into the civilian market place. How well will it reload? What interesting things will be done with the technology when you apply it to uses other than military?

It is my firm conviction it will go the way of true velocity.....

AJC1 said:

It is my firm conviction it will go the way of true velocity.....

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The cartridge doesn't make lots of sense to me as the standard issue.

N555 said:

Seems it's only a matter of when, not if.
Do we think this will inspire a new generation of wild cats?
Or say just necking it to 308, effectively upping the pressure of 308 to 80,000psi, or doing the same thing to 6.5creedmoore?
Obviously no one will be able to buy 308 fury or 6.5 creedfury so will have to make it.

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I was just discussing this the other day with somebody. I will be interested to see how it plays in the reloading community. The case is a 3 piece design with a stainless steel head, so that seems to me that there will be some sort of special dies required to handle that SS head and AL locking ring, not to mention it will be super expensive and unobtanium for years, lol. I can't imagine Sig isn't hasn't patented that design, and Sig will be the ONLY producer of that 3-piece brass. As far as civilian shooters go, I would guess that there will be an all brass version of the cartridge that will be of a reduced pressure that will become what most people shoot most of the time, with the full 80K pressure 3 piece cases being used for things like super long distance match shooting. It will definitely not be general issue for the military, it's geared for basically the next gen designated marksman/sniper role.

EricBu said:

As far as civilian shooters go, I would guess that there will be an all brass version of the cartridge that will be of a reduced pressure that will become what most people shoot most of the time, with the full 80K pressure 3 piece cases being used for things like super long distance match shooting.

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That is what Sig is already cataloging.

https://www.sigsauer.com/elite-ball-fmj-277-sig-fury.html
https://www.sigsauer.com/accubond-277-sig-fury-hybrid.html

Hmmm.
We already have have ".260 Remington" (essentially a .308 Win necked down to to 6.5mm). In function - with a proper twist rate - a modernization of the 6.5x55mm Swede in that it uses a 'standard' head size (all the XXx57 Mausers and the US 30-06 and 7.62x51mm cases) in a 'strong' action;
a "7mm-08" which is a .308 Win necked down to 7mm, which is essentially a 7x57mm Mauser shortened and made for 'strong' actions;
the 6.5 Creedmore a shortened and less powerful version of the .260 Remington (see above);
and the 6.5 Grendel, a reworked and necked up version of the 220 Russian cartridge which has less snap than the 6.5 Creedmore.

Why not? I'm holding my breath for a .500-08, myself.

Archie said:

Hmmm.
We already have have ".260 Remington" (essentially a .308 Win necked down to to 6.5mm). In function - with a proper twist rate - a modernization of the 6.5x55mm Swede in that it uses a 'standard' head size (all the XXx57 Mausers and the US 30-06 and 7.62x51mm cases) in a 'strong' action;
a "7mm-08" which is a .308 Win necked down to 7mm, which is essentially a 7x57mm Mauser shortened and made for 'strong' actions;
the 6.5 Creedmore a shortened and less powerful version of the .260 Remington (see above);
and the 6.5 Grendel, a reworked and necked up version of the 220 Russian cartridge which has less snap than the 6.5 Creedmore.

Why not? I'm holding my breath for a .500-08, myself.

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But why not 338 federal

N555 said:

Same here.
I don't see any benefit replacing 5.56mm with 6.8x51, but the 6.8x51 seems to be of other value even if you don't get on the XM5 or 6.8x51 bandwagon.

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My understanding is that the Army wanted a round that could penetrate body armor, which has become the norm amongst the world's major armies. The 5.56 does not have the power to get the penetration the Army wanted.

N555 said:

We don't care what the army does, we just want to benefit from what they make using our tax dollars.
I say it's about time we get something readily usable.

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Can somebody tell me if N555 is serious, or if he is trying to be funny? I would prefer somebody other than N555, because I would probably have the same problem with his response.

It looks like a very expensive path back to 7.62 Nato. @ 80k+ psi, i cannot imagine there will not be metalurgical issues. Makes no sense to me when we have 762 systems on the shelf. All it reallyy ofers is flatter trajectory. Not really nessesary w militery grade sights.

AJC1 said:

But why not 338 federal

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The .338 Federal is a reasonably useful round. As many of the others, it is based on the .308 Win case. This time, necked up to .338 caliber and will still fit in a medium length strong action. I like this version better than those of the belted magnum fad (but I don't like belted magnums in the first place) and it does not require a long action rifle.
I didn't include above as I am making a concerted effort to not be long winded.

N555 said:

I don't see any benefit replacing 5.56mm with 6.8x51, but the 6.8x51 seems to be of other value even if you don't get on the XM5 or 6.8x51 bandwagon.

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Changing the cartridge will entail changing the rifle. Which is okay with me. I have been unimpressed with the M-16 (and variants) since 1969, the first time I fired the silly thing. Nor am I convinced the round is sufficient.
The 7.7x51mm (.270-08) cartridge is too long to fit in the current M-16 action and I'm pretty sure the M-16 action will not handle 80,000 psi for many rounds.

N555 said:

We don't care what the army does, we just want to benefit from what they make using our tax dollars.
I say it's about time we get something readily usable.

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Sounds rather logical to me. What the "Army" - actually the Department of Defense ergo the Federal Government - decides has a great deal of international - think 9x19mm handgun round - and intranational - politics - think stupidity. Aside from a defensive capability standpoint, it doesn't mean much.

However, the amount of money (tax money) does produce some valuable information. This results in some valuable changes in technology in the firearms and other fields. Both the .30-06 Springfield and the 7.62x51mm rifle rounds are essentially 'Army' developments. No doubt there are others. I don't think N555's comments are at all sarcastic or silliness. They are more factual than many folks like, but that's life.

Bcwitt said:

It looks like a very expensive path back to 7.62 Nato. @ 80k+ psi, i cannot imagine there will not be metalurgical issues. Makes no sense to me when we have 762 systems on the shelf. All it reallyy ofers is flatter trajectory. Not really nessesary w militery grade sights.

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With modern actions and normal not furry pressures 6.5×55 would be a hell of a lot cheaper... throat life is going to end this I'll bet...

N555 said:

I think 80,000psi could definitely be a barrel killer. I say let's find out. I want to find out.
If not 80,000, then maybe a more reasonable 70,000psi.

So far no one had been like "omg if you put 80,000psi in a Mauser style or 700 action it's going to blow up" so that's good. The weak point in the system had always been the brass.
Might be advantageous to select a platform for an 80,000psi gun that the barrels can be user replaced.
Who has the easiest to swap bolt action barrels, is it still savage and ruger?
I know M70 style, rem700, Mauser pretty much need a gun smith

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One time failure is unlikely as proof tests occur... now metal fatigue due to a steady diet of 80k psi loads is entirely different... action replacement then becomes a factor that no one currently practices...

Given that Sig won the competition against several other very capable companies. In winning this competition I would be willing to bet tens of thousand of rounds (probably well more than 100,000 rds) were fired both in Sig's own internal testing and then in evaluation by the Army with the bid samples submitted with their proposal. I am guessing they have all the major and most of the minor technical challenges (including the high pressure) of the system fairly well ironed out. With the award of the program the Army is initially going to buy 25 more rifles and 10 machineguns and a heap of ammo. If the Army does their job they will abuse these rifles in as many ways as they can over the next few months. If there is going to be an issue it will be discovered (hopefully) before the X is drop from the XM-5 and XM-250.

The Army and various industries have been doing alot of R&D on coatings, new alloys, and differential heat treating techniques, these technologies can be used to extend barrel life (along with many other application). Most of these technologies are currently prohibitively expense for the civilian gun market but are slowly maturing and may find a use when the XM-5 and XM-250 become fully fielded systems.