6.8 Rem v. 6.5 Grendel in Iraq?

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That's an unfired .30 Remington round.

Not that similar, then - the shoulder angle is quite different.
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The fired brass from my .30 Remington Model 8 rifle looks a lot closer to the .30-30 Winchester's.

And Remington's reason for the round was to duplicate the .30 WCF/.30-30 Winchester's ballistics in an autoloading/pump rifle. So case capacity was the biggest factor. The shoulder design was probably tweaked to enhance feeding from the box magazine of the Browning-designed Model 8, just like the removal of the rim.

On a side note, I'm working with the Lapua and Lost River Ballistics 6.5mm offerings on my larger 6.5mm rifles. I've got to get busy on my 6.5 SPC/.26 Remington AR-15 project - .277, indeed! ;)
 
The shoulder design was probably tweaked to enhance feeding from the box magazine of the Browning-designed Model 8, just like the removal of the rim.
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Actually I suspect that the shoulder was made sharper because of the absence of the rim, in order to provide accurate headspacing.

Tony Williams: Military gun and ammunition website and Discussion forum
 
It would appear that little has changed in the positions of the interested parties in the last 8 months. I went back and found:http://www.thehighroad.org/showthread.php?t=77366&page=1&pp=25&highlight=6.8+spc I reread the posts of 8 months ago and find no consensus seems to have formed. The proponents of both cartridges still expound their virtues, while there remain some doubts about both.

There have been some developments. Several companies now produce 6.8 SPC barrels and uppers. Bolts are available, as are reliable magazines. Bulk brass for the 6.8 SPC has become available (if on an inconsistent basis) and loaded ammo is available from small volume loaders.
At one other company has been permitted to produce 6.5 Grendel parts. Brass and loaded ammo are available.

I believe the major stumbling blocks are feed reliability in the 6.5 and the inability of the 6.8 to meet performance goals at acceptable pressures. If I had to pick one (in an AR) today it would be the 6.8 SPC.

David
 
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David wrote: "If I had to pick one (in an AR) today it would be the 6.8 SPC."

Well enough, but the question I find interesting in these discussions is, "Why?" Care to expound?

John
 
I saw 6.8SPC ammo at a vendor at the Denver gunshow this weekend. He had at least three boxes of 115gr OTM at about $12.50 per box. It was not Remington, but some other smaller manufacturer (not PCA).

I spoke to somebody recently who had shot about a case (1k) through the Barrrett 468, sometime in the last month or two. He said it was running perfectly. The latest lots of the testing ammo were running about 2500-2530fps from the 12". That should meet the 2800fps published number but from an 18" barrel (instead of 24").

-z
 
Grendelizer,

If I were in Iraq, Afghanistan, Pakistan, etc. and subject to being shot at 24/7, the bit of extra reliability I imagine the 6.8 SPC to possess would easily outweigh the Grendel’s “advantagesâ€, even if the return were doubled.

IF I wanted an AR for long range target competition, then the Grendel might be an option. If AA can convince me that they can build rifles that will feed reliably from untweaked production mags, a major US manufacturer tools up to produce brass and they drop the “proprietary†marketing and set their sights on selling things, the 6.5 Grendel will take a huge step forward. If AA continues to try to treat the cartridge like the product instead of uppers, brass, mags, dies, ammo and parts, the 6.5 Grendel will be nothing more than an entry in COTW. It will be a shame too, because the cartridge is a fine design for many applications and the brass they import is top notch.

Zak,

You’ll have to forgive me if I’m a bit skeptical of the velocities. I know that with the resources available to the major manufactures they can do some amazing things. I don’t doubt that a cartridge specific powder could be developed and combined with new packing techniques can get velocities above and beyond what I can produce by handloading. Until green and yellow boxes are just a phone call away and everyone can clock them for themselves, I’ll have some doubts. When you get your hands on some OTC production ammo from big green and run it across your chrono, I’ll not question your results.


David
 
If better 7.62x39 ammo were available, would that change things?

Something like Mk 262 Mod1, an improved performance cartridge.
 
I think that would be difficult, because the 7.62x39 was designed with a large-calibre, short bullet. if you loaded it with a long, heavy bullet comparable with the Mk 262 in 5.56mm then the muzzle velocity would drop dramatically, partly because of the extra weight, partly because to keep the overall cartridge length the same (essential to operate in the gun) the bullet would have to protrude deep into the case, reducing the propellant capacity.

What you would need to do to improve the long-range performance would be to reduce the calibre to, say, 6.5mm, then straighten the case a bit to improve the propellant capacity, then voila! You have the 6.5mm Grendel :D

Tony Williams: Military gun and ammunition website and discussion
forum
 
How much extra performance would we get by blowing the Grendel's shoulder forward another 3mm and ditching the 120+ grain bullets? Even with the great BCs and marvelously small amount of wind drift, I believe that the heavier bullets reduce the first-round hit probability with their more rainbow-like trajectories.

Looks to me like the 100-107-gr bullets come close enough to M80 Ball performance (a tad better, IIRC) to allow a reasonable substitution for both 5.56mm and 7.62x51 ammunition in the supply/arms chain.

And what's really the advantage of 6.5mm over 6mm anyway? Tubb's 6XC is too much like a .243, it's too long for AR magwells (should that REALLY be a major consideration???), and it gets too few rounds per pound of those military metals to be a *wise* choice...but it's a super-accurate 6mm...
 
Actually I was wondering about short range performance. Increasing the wounding potential. If I recall correctly, the 6.8mm was developed to provide increased short range effectiveness.

Our military already has tons of weapons far more effective at long range than a rifle.
 
This whole argument of 6.8 vs 6.5 or 200 vs 35000 is entirely stupid because of the artificial case length restriction.

Facts -

The AR-15 provides less than acceptable battlefield reliability and maintainability.
The 5.56x45 nato provides less than acceptable ballistics.
Trying to cram a heavier bullet with better ballistics in a short cartridge results in less than acceptable velocities.

Answer:

Design a new rifle to fire a new cartridge!!!
Use a longer cartridge length to accomodate a longer bullet and provide enough powder to give desired initial velocity and acceptable long range performance.

:cuss:
 
BNO, I disagree. While it's true that a case length is "artificially" or "arbitrarily" chosen, I think the current OAL of the 5.56/6.8SPC/6.5G is both useful and necessary because it disciplines gun and cartridge designers to keep their designs as compact and lightweight as possible, which is also a consideration in the overall picture of a military round. We can't focus purely on "maximized" performance of the round itself, without any consideration of the other factors of size and weight.

Everything in cartridge and weapon design is a compromise, but we're looking for the "optimum compromise"!

John
 
The 77gr Mk262 5.56 ammunition has a velocity in the same ballpark as both 6.8SPC and 6.5 Grendel loads. The 77gr is superior to M193 w.r.t terminal ballistics at any range from any barrel length (with the possible exception of barrier penetration). Thus your argument about velocity is poor.

Grendelizer is right on about size and weight of the platform itself. Think about a 12"-barrelled "M4" used while mounted (vehicle). In 5.56-length cartridges including 6.8, this is a viable platform for rapid aimed fired, aimed burst, and controlled full auto fire. A 12" 308 will be much heavier, make for a larger weapon, and will be much harder to control.

-z
 
While I agree with Zak and John about the need to keep the platform as trim as possible, I don't think weight (or size) would really be much of a factor in lengthening the receiver of an AR 15 10mm. The problem would be one of cost.

I see larger rounds being adapted to the AR platform as an interim measure. We have learned a lot on the last 50 years that isn’t reflected in the AR. While it is a mature system, I think the time has come to think about replacing it and the 5.56.


David
 
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I don't think weight (or size) would really be much of a factor in lengthening the receiver of an AR 10mm. The problem would be one of cost.
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The difference in the OAL of 308 and 223 is only 0.5 - 0.7", but look at how much larger the AR10 receiver and BCG are vs. the AR15's.
 
It seems that it would take only .20 of an inch, or 5mm, longer in the mag length/case length to get our 105-gr or so 6.5mm bullets reliably up to the speeds which meet or exceed the M80 ball trajectory AND significantly improve on the wind drift figures. Ammo stays lighter than 7.62mm stuff, you might could stay with the slightly smaller SPC case body for insignificanly (IMO) better ammo stacking, and you would also have a chance then to design greater safety margins in the bolt lugs. . . AFIK, the bolt thrust is a factor for ammo pressures in BOTH the SPC and the Grendel.

Both are, really, stopgaps with various compromises to fit in the M16-size AR package. Stretch that lower to move the trigger group back for the bigger mag well (but keep the assembly pin locations the same), and the upper might need no changes to make it work? Looks to me like the bolt carrier traveling back 5mm farther to pick up the round would affect only the buffer. All other parts would stay the same, though I would argue for an M1 Carbine-style tappet piston at the end of the gas tube...maybe.

Cast in some sand cuts in the upper and put a few in the bolt carrier and the AR might be easier to keep running in the crud.

Seems we're married to the current system by virtue of existing magazines, just like we wound up married to the '06 after WWI because of the ammo on hand. But since we're low on ammo and the cost of the average grunt's ammo fired in combat far exceeds the costs of those magazines, why not just make the next rifle a better round that will let us again unify major parts of the supply system. REPLACE ALL 5.56mm AND 7.62mm with ONE ammunition that has advantages over both. Done right, the only "compromise" from the 7.62mm will be slightly lower kinetic energy...but that's what the .50 is for anyway. :cool:
 
The AR-15 provides less than acceptable battlefield reliability and maintainability.
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BS, this hasn't been an issue since the early 60s, and we don't use the AR15.

The 5.56x45 nato provides less than acceptable ballistics.
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Says who? There's been some "anecdotal statements made by a few people", a few instances where the enemy was engaged at ranges exceeding the weapon's effective range, (the enemy's weapons were also outside thier effective range by the way) but I haven't heard any responsible military officer who has any empiracle evidence make such a statement.

Trying to cram a heavier bullet with better ballistics in a short cartridge results in less than acceptable velocities.
Click to expand...

True, and the military has nothing to do with these experiments... a few entrepreneurs do.

Design a new rifle to fire a new cartridge!!!
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No "need" has been proven for either.

You can't take "exceptional instances" and condemn a rifle/cartridge because of them.

There is no "wonder gun" or "wonder cartridge" or "wonder bullet" that will fill every percieved need for every imaginable circumstance.

If someone comes up with one, rest assured we'd be buying it.

Military procurement of weapons and materials are always going to be the best compromise that will fit the needs of the military over a wide range of potential requirements/uses.

That's the way it is and the way it must be.
 
ZAK, I've followed your posts on this thread quite a bit... there may be a "unit" that is somehow testing this of their own volition and if that's the case then the "contractor" is supplying the ammo and equipment for the tests, but the "Army" sure isn't testing it... or put it this way, they don't know that they're testing it...which would be worse...

I can find nothing that shows that any such testing has been authorized or funded and I feel I have pretty good sources... as it used to be my job to oversee many of same.

Small arms testing is not something the Army has ever shown a habit of being secretive about.

So all the things I've read that would indicate this is somehow "hush-hush" makes me take it even less seriously. There simply would be no need for it and it costs a lot more money to test and evaluate something on the "sly", and the funding is MUCH harder to get to do it.
 
There's been a few write-ups in the various gun rags about the 6.8spc and they all state that the cartridge was developed (even gives the names) by a couple of NCO's and it has been "purchased" by the groups they're affiliated with. If I remember right they were part of one of the special forces teams and didn't have to go through the normal government procurement.

I'm not 100% sure but I think I read one article in a "Guns & Ammo" that came with a Surefire flashlight I bought..

Have a good one,
Dave
 
Would it even be necessary to develop a new cartridge, even if you were going to totally replace the existing weapons and magazines.

Why not simply apply a touch of modern tech to the old Brit EM2 and its 7x43mm round?
 
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