More than a rifle: How a new 6.8mm round, advanced optics will make soldiers, Marines a lot deadlier

[rangerrebew]

More than a rifle: How a new 6.8mm round, advanced optics will make soldiers, Marines a lot deadlier

By: Todd South  


For decades, small arms advocates have pushed for a replacement for the M16/M4 weapons carried by most soldiers, Marines and special operators.

And despite long-running programs that have come on the scene and later floundered before being canceled, the much revised 5.56mm weapon and its similarly chambered light machine gun counterpart have continued to be the mainstay of squad-level firepower.

But news over the past year, from the secretary of defense to service chiefs and heads of small arms programs across the force, has revealed the potential for an actual replacement of the weapon first delivered to troops more than half a century ago.

https://www.militarytimes.com/news/your-army/2018/12/10/more-than-a-rifle-how-a-new-68mm-round-advanced-optics-will-make-soldiers-marines-a-lot-deadlier/?utm_campaign=New%20Campaign&utm_medium=email&utm_source=Sailthru&utm_term=Editorial%20-%20Marine%20Corps%20-%20Daily%20News%20Roundup

[Elderberry]

I'd wish they'd pick the 6.5Grendel over the 6.8SPC, but that's just cause I've got the Grendel. Really, there's not a lot of difference between them.

6.5 Grendel vs. 6.8 SPC vs. .223 Rem. Cartridge Comparisons

Nominal Parameters        6.5 Grendel        6.8 Rem. SPC    .223 Rem.
Case length (inches)         1.520                  1.686                   1.760
Maximum Cartridge
Length (inches)                 2.260                  2.260                   2.260
Cartridge Head
Diameter (inch)                  .441                  .422                   .378
Max Av Pressure (psi)   52,000               55,000               55,000
Bullet Weight (grains)         120                  120                     62
Ballistic Coefficient        .457                 .400                  .310
Muzzle velocity (fps)       2,500                 2,400                 3,000
Vel at 500 yards (fps)   1,678               1,505                1,908
Muzzle Energy (ft-lb.)      1,666               1,535                1,239
E at 500 yards (ft-lb.)    750                 604                  502

[bigheadfred]

Re: More than a rifle: How a new 6.8mm round, advanced optics will make soldiers, Marines a lot dead

Somehow the truncated title doesn't come across very well.

Why not just give them back the M1? @Elderberry

[Elderberry]

Re: More than a rifle: How a new 6.8mm round, advanced optics will make soldiers, Marines a lot dead

Somehow the truncated title doesn't come across very well.

Why not just give them back the M1? @Elderberry

Not that I'd object to that (I have 2 Garands), but I think they are attempting to choose a round that will replace both the .223 and the .308. So they are looking for something between the two. But they have recently upgraded the bullets for both of them. Why change them now?

They have done these studies for so many years now, I'll be surprised if they actually make a change.

[bigheadfred]

Not that I'd object to that (I have 2 Garands), but I think they are attempting to choose a round that will replace both the .223 and the .308. So they are looking for something between the two. But they have recently upgraded the bullets for both of them. Why change them now?

They have done these studies for so many years now, I'll be surprised if they actually make a change.

The armor-piercing and better optics look good on this new one.

Wasn't the .223 bullet supposed to have a tumbling effect (on impact) that was supposed to increase kill capacity to offset it's lighter weight?

I would as soon have a larger bullet with knockdown dead power. But I have only been a hunter of animals and not people.

[Elderberry]

Wasn't the .223 bullet supposed to have a tumbling effect (on impact) that was supposed to increase kill capacity to offset it's lighter weight?

Yes. The .223 bullet, as well as many other bullets, become ballistically unstabilized once they enter the body, and yaw causing more tissue damage.

[bigheadfred]

Yes. The .223 bullet, as well as many other bullets, become ballistically unstabilized once they enter the body, and yaw causing more tissue damage.

All I have is a .270. A jacketed soft point 130 grain bullet has produced many one shot kills. Good mushroom without much defragmentation.

[Bigun]

All I have is a .270. A jacketed soft point 130 grain bullet has produced many one shot kills. Good mushroom without much defragmentation.

Your .270 is 6.8mm.  They chose wisely IMHO. 

IF I could only own one rifle it would unquestionably be my .270 !

[Elderberry]

All I have is a .270. A jacketed soft point 130 grain bullet has produced many one shot kills. Good mushroom without much defragmentation.

The same bullet weight I  use hunting with my 6.5X47 Lapua. I also plan using a 130 gr. bullet in my 6.5Grendel for hunting(Haven't hunted with it yet).

My #1 hunting buddy only uses his .270 for many years. For deer, hog, red stag, elk, whatever comes along. He doesn't reload, but saved all his empties. I just recently used a lot of his 270 brass to form cases for my new addition, a .358Yeti barrel I picked up for my AR.

[rangerrebew]

I think they are attempting to choose a round that will replace both the .223 and the .308. So they are looking for something between the two.

Something between the two at the lowest possible price, of course.

[Elderberry]

Something between the two at the lowest possible price, of course.

From the same folks that thought paying $90.00 for a hammer was reasonable.

[bigheadfred]

From the same folks that thought paying $90.00 for a hammer was reasonable.

More like $400.

I paid $120 for my Stiletto framing hammer. Now they cost more.  It doesn't wear your arm out--less shock, lighter weight--than a regular framing hammer.

[Elderberry]

Dang! What's it comin' to?

I thought my Estwing was a good hammer.

[bigheadfred]

Dang! What's it comin' to?

I thought my Estwing was a good hammer.

The wear and tear, the older I got, was the decider. A guy I worked with got one. I thought he was nuts, paying that much for a hammer. Until I gave it a try.

[Elderberry]

Well this is the hammer(axe) I swung the most, but that was many yrs ago.

[the_doc]

Yes. The .223 bullet, as well as many other bullets, become ballistically unstabilized once they enter the body, and yaw causing more tissue damage.

A Marine Gunnery Sergeant once told me during the Viet Nam era that the NVA and VC called our M-16A (5.56mm) "the little black gun with the little-bitty bullet that makes a great big hole." 

We formerly supposed that the bullet yaws in flight, producing a flatter, blunter shock wave, which actually made me wonder how this could be a very accurate bullet.  (Maybe so, but...)  Now I'm hearing from multiple sources that the experts now believe that the bullet starts its yawing only on impact (due to the shape and weight distribution of the slug?).   

[bigheadfred]

A Marine Gunnery Sergeant once told me during the Viet Nam era that the NVA and VC called our M-16A (5.56mm) "the little black gun with the little-bitty bullet that makes a great big hole." 

We formerly supposed that the bullet yaws in flight, producing a flatter, blunter shock wave, which actually made me wonder how this could be a very accurate bullet.  (Maybe so, but...)  Now I'm hearing from multiple sources that the experts now believe that the bullet starts its yawing only on impact (due to the shape and weight distribution of the slug?).   

I was always under the assumption it was a close-range weapon so the overall, longer range accuracy wasn't as big of a factor.

[Elderberry]

http://www.olyarms.com/index.php?id=14&option=com_content&task=view

Distinguished forensic pathologist Dr. Martin L. Fackler, observed when he was conducting wound research for the U.S. Army several years ago ("Wounding Patterns of Military Rifles," International Defense Review, Volume 22, January, 1989), that in tissue simulants such as ballistic gelatin, , the 55-grain, M-193 military bullet lost stability, yawed (turned sideways) 90 degrees, flattened and broke at the cannelure (groove around the bullet into which the cartridge case is crimped) after penetrating about four to five inches. The forward portion of the bullet generally remained in one piece, accounting for 60% of its originally weight. The rear, or base portion of the bullet, broke into numerous fragments that may also penetrate tissue up to a depth of three inches. Dr. Fackler also noted that a relatively large stretch cavity also occurred, violently stretching and weakening tissue surrounding the primary wound channel and its effect was augmented by tissue perforation and further weakening by numerous fragments. An enlarged permanent cavity significantly larger than the bullet diameter resulted by severing and detaching tissue pieces. However, as the range increases, the degree of bullet fragmentation and temporary cavitation decreases because terminal velocity diminishes. At 100 meters, Fackler observed that the bullet, upon penetrating tissue, breaks at the cannelure, forming two large fragments. However, beyond 200 meters, it no longer looses its integrity, although flattening continues to somewhat occur out to 400 meters.

[Bigun]

A Marine Gunnery Sergeant once told me during the Viet Nam era that the NVA and VC called our M-16A (5.56mm) "the little black gun with the little-bitty bullet that makes a great big hole." 

We formerly supposed that the bullet yaws in flight, producing a flatter, blunter shock wave, which actually made me wonder how this could be a very accurate bullet.  (Maybe so, but...)  Now I'm hearing from multiple sources that the experts now believe that the bullet starts its yawing only on impact (due to the shape and weight distribution of the slug?).   

Many of the Iraq and Afganistan vets I've spoken to tell me that they had to shoot the same guy 3 or 4 times to put him down with the .223 and the standard 200 round combat load being insufficient for that reason. 

200/3 = 66 effective shots avalible. 

[Elderberry]

I was always under the assumption it was a close-range weapon so the overall, longer range accuracy wasn't as big of a factor.

https://blog.cheaperthandirt.com/m4-carbine-750-yards-beyond-simple/

The M4 Carbine at 750 Yards and Beyond: Three Simple Things to Know

A standard AR-15 with a non-free floated barrel is far more accurate than many shooters think, and it makes sense if we consider how an AR-15 is built. It doesn’t have a complex, multi-faceted action to bed, operating rod or finicky top handguard like other military rifles (we’re looking at you, M14 and M1A). In theory, the AR-15 is actually configured more like a standard bolt-action rifle in terms of how the barrel is mounted to the receiver and how the handguards interact with it: straight in, with consistent outside influence. This makes the overall design inherently accurate, and the fact that an AR-15 doesn’t need bedding helps as well.

Quality ammunition will make a bigger difference at 750 yards than a match-grade rifle will. Take an off-the-rack M4 carbine to the range with excellent ammunition, and you’ll likely see better results than you would with a custom-grade rifle shooting crummy ammo.

Switching to the higher quality bullet and hand-weighed powder charges made a night and day difference. We went from occasional hits at 500 yards to consistent performance all the way out to 750 yards.

With high-quality ammo, making contact with the 18-inch x 24-inch steel plate at 750 yards was simply a matter of calling the gusting winds correctly. The 10-inch plates were slightly more difficult, and required a precise elevation hold and exact wind call.

[the_doc]

I was always under the assumption it was a close-range weapon so the overall, longer range accuracy wasn't as big of a factor.

The M16A is definitely not a sniper rifle like the .308 or the .338 Lapua Magnum, but Wikipedia says that that the M16A1 is very accurate out to 300m and still useful out to 500m (87% "Hit Probability"). 

[bigheadfred]

https://blog.cheaperthandirt.com/m4-carbine-750-yards-beyond-simple/

Thanks for the upgrade.

[Bigun]

The M16A is definitely not a sniper rifle like the .308 or the .338 Lapua Magnum, but Wikipedia says that that the M16A1 is very accurate out to 300m and still useful out to 500m (87% "Hit Probability").

Hits are one thing and stops are quite another!

[the_doc]

Many of the Iraq and Afganistan vets I've spoken to tell me that they had to shoot the same guy 3 or 4 times to put him down with the .223 and the standard 200 round combat load being insufficient for that reason. 

200/3 = 66 effective shots avalible.

I would guess that the longer shots would be problematical, not from an accuracy standpoint, but from a lethality standpoint--so yeah, it would be a better close-in weapon in that regard.  I would assume that many of the shots in the jungle areas of Nam were close-range (although there were surely a lot of longer shots across, say, rice paddies).