New US Army Primary Rifle Round

[KChen986]

Bartholemew Roberts has consistently mentioned the 77gr ( I think?) 5.56 round that performs about as well as a standard 6.8.

If that's the case then there's almost no need to convert existing weapons and shift logistics to support the 6.8.

Besides, doesn't the 5.56 frequently fragment and cause huge wound channels?

 

[TheManHimself]

Indeed. Current 5.56mm FMJ and OTM rounds will fragment violently in soft tissue out to around 200m. Even beyond that distance the bullet will yaw, producing wounds similar to the Russian 5.45x39mm round the Afgans called the "poison bullet" back when the Soviets invaded Afganistan.

Regarding the OP, 6.5 Grendel is dead as a military cartridge. 6.8 SPC fills a niche in performance in the short-barreled (10.3" rifles) the go-fast guys are using, along with the 77gr 5.56mm Mk 262 load. Servicewide replacement with 6.8 SPC is much less likely than more widespread replacement of the M855 round with Mk. 262, which as noted provides nearly identical terminal performance as 6.8 SPC out of 14.5" and longer barrels.

Current loadings of the 5.56mm cartridge as used by the US military are only "ineffective manstoppers" in the eyes of people who have never used them on human beings.

 

[Chui]

The 5.8 is *NOT* inferior at all to the cartridges mentioned. It actually penetrates steel plates much better than either. Soldiers wear armor. They'll be injured pretty badly with the 5.8 Chinese cartridge. It also puts more energy on the target at longer ranges. The 6.8SPC is demonstrably better but the 5.8 is demonstrably better as a battle cartridge than the 5.56 and 5.45. There have been three articles discussing the capabilities of the cartridge and the only conclusion I recollect is that:

While the cartridge performs admirably against troops wearing armor it's terminal performance on unarmored personnel may not be as impressive. Big deal. It will deny cover better; carry more energy down range and it's made to engage front line troops (wearing ballistic armor). I'd take it.

 

[VonFireball]

With Obama planning to expand the number of people in the military while cutting expenses, I doubt there will be any money to upgrade much of anything.

Hi-Point Carbines and pistols...lol

 

[Chui]

It will/should/could boil down to the cost of producing either cartridge. An OTM 6.8 will perform far better than a 77 gr 5.56 OTM cartridge. Neither are 'inexpensive' to manufacture. Given a choice (we won't) I'd opt for the 6.8 SPC. No need for an OTM projectile which is essentially a Sierra Match King or Hornady projectile. I forget which.

 

[SPUSCG]

the military will take there sweet time changing to better rifles. Although it would be relatively cheap. Give up one stealth bomber and you have money for new rifles for every us soldier. A FN scar in 6.5 grendel would be nice. piston operated m4s in 6.5 too.

 

[dm1333]

Can anybody post a link to any tests or articles about the bonded bullet Bartholomew Roberts mentioned. I'm curious and Michigan winters are long so I have plenty of time to read.

 

[RockyMtnTactical]

The 5.56 is gonna be the standard round in the military for some time...

 

[Chui]

While I can't post an article you can look up "ATK, Federal, .223, performance, .pdf" and see what you get.

Or just go here: http://le.atk.com/pdf/SanAngeloWBW_Report.pdf

 

[IZinterrogator]

I'm going to throw that at my Intel Analysts today and see how they respond!

So had they heard it before? They should have, it's usually the most common form of military intelligence.

 

[troy_mclure]

Current loadings of the 5.56mm cartridge as used by the US military are only "ineffective manstoppers" in the eyes of people who have never used them on human beings.

ive fired quite a few mags of 5.56 "in anger" it has a highly unimpressive terminal performance from an m4.

most of the guys we shot had 2 clean holes per bullet. we had one guy that had 19 in & outs, and survived.
i dont think the current issue 5.56 cartridge reaches enough velocity to fragment from the short bbl m4's.

 

[Rifleman 173]

I am testing a Rock River lower with collapsing stock to which I have attached an upper half from Model "1" Sales. The upper I opted for is one that uses the 7.62 X 39 round. I get the ergonomics of an M-4 type carbine but I get to shoot the larger round. It seems like the best of both worlds. Something that you might want to also consider doing if you don't like the .223 round, which I don't and have used in combat, and want to try something else for more effectiveness. Thus an M-4 boomstick that shoots 7.62 X 39 ammo.

 

[Al Thompson]

Rifleman, what's the magazine capacity on that 7.62x39 M4 platform?

 

[jsmaye]

Hi-Point Carbines and pistols...lol

The calibers would be a bigger issue than the actual HP hardware. Plus, think of the advantages of the lifetime warranty...

 

[Bartholomew Roberts]

Just my opinion but I don't think that 6.8 is quite dead yet but it's major advantage lies in shorter barrels. 5.56 ballistics aren't all that impressive from a 16" barrel.

Well, the link below compares the 5.56 to the 6.8 at basically the same velocity (about 2,600fps). It seems to me like it will be easier to get a 5.56mm going faster out of a short barrel than it will to speed up a heavier 6.8.

Can anybody post a link to any tests or articles about the bonded bullet Bartholomew Roberts mentioned.

Check out Page 12 of this presentation from the 2008 NDIA Small Arms Symposium for more information on the Federal 77gr bonded load. The whole PDF is a good read for those interested in terminal ballistics, as are these two links from the same symposium:

The Ultimate Caliber - Myth or Reality
After-barrier effectiveness of Small Arms ammunition

ive fired quite a few mags of 5.56 "in anger" it has a highly unimpressive terminal performance from an m4.

Check out the 77gr Federal link above. It describes a phenomenon called "fleet yaw". Basically, the same lot of ammo might behave wildly different between two different M4s based on individual characteristics of the rifle. It is one reason why it has been difficult to quantify M855 performance (though it seems to be a problem across many rounds that tends to disappear as rounds get bigger).

 

[dm1333]

Thanks. My google search wasn't turning up anything like the .pdf you provided.

 

[dm1333]

Thanks for those links to the .pdfs. They were very informative and the initial cost for developing the 6.8 shocked me a little. We have the same problem in the Coast Guard, things get shoved down our throats from the top instead of the field units being asked what would work best. It is slowly changing though.

 

[Rifleman 173]

My magazines for my carbine are 10 and 30 rounders. Both came from C Products, LLC. This is where I got my 30 round magazines:

http://www.cproductsllc.com/shop/product_info.php?cPath=22_36&products_id=59

 

[FDE007]

My very first Colt rifle was a CAR15 that had the slow 1:11 (Vietnam Era) twist rifling. Accuracy was compromised over 150 meters, however these bullets tended to tumble upon entry.
IMHO the attempts to make this cartridge more "accurate" at extreme ranges has had a detrimental effect on its terminal performance.
Perhaps the US military can return to the unstable / tumbling bullet model with less effort than a whole new cartridge?

 

[Bartholomew Roberts]

All spitzer bullets tumble on impact whether the twist rate is 1:12 or 1:7. This is because the lighter nose slows down more rapidly than the heavier base and the round yaws. In order to spin-stabilize a spitzer projectile in a human body, you would need rifling like a machine screw thread. So the only thing reducing the rate of twist would do is limit you to shorter and lighter bullets - which is a bad thing if you are relying on yaw and fragmentation as the wound mechanism.