Army Marksmanship Unit match grade ammo requirements for 6.8x51mm

[cmshoot]

Big question is WHY?
I would think it would cost more as well.
All brass has worked well for a long time.
If it's gonna be discarded anyway, wouldn't steel be cheaper?

For this case to work, it needs to be a combo of stainless steel and brass.

The head/web of the case needs to be stainless steel to contain the high pressures this cartridge needs to generate the velocity they are looking for.

The front of the case needs to be brass so that it will swell when the powder charge is ignited, fire-forming to the chamber and sealing it. The brass then shrinks down slightly, aiding in extraction.

Steel cases won’t do this. This is one of the reasons that steel-cased ammo is so “dirty; it doesn’t swell to seal the chamber, and some of the powder blows back around the casing, leaving deposits in the chamber and action.

So, stainless steel where it needs to be strong and rigid, and brass where it needs to be flexible.

 

[cmshoot]

Sounds hot but how about the drift?
it looks like they should be shooting about 160 grains to cut the wind.

Probably too hot for my old shoulder.

With all things being equal, the faster the bullet, the less the wind drift. The less time the bullet is in the air, the less time wind has to interact with it.

So, the 6.8x51mm would exhibit less wind drift than the 6.5 Creedmoor when using the same bullet at the same distance.

6.5 Creedmoor exhibits less wind drift than .308, when comparable loads are used.

 

[7pt62THOR]

Still have to ask, WHY?
This is not a sniper round but a ground pounder's shoulder fired round.
Most targets will not be engaged at great distance, therefore no great need for a pill with less drift.
JuSt CuRiOuS...

 

[cmshoot]

Still have to ask, WHY?
This is not a sniper round but a ground pounder's shoulder fired round.
Most targets will not be engaged at great distance, therefore no great need for a pill with less drift.
JuSt CuRiOuS...

You’re wrong in that. Look at post #1 again. These are the requirements of the Army AMU for “Match Grade Ammo”. The two bullets selected by the AMU are the Sierra Match King and the Berger Hybrid Hunter, both known for their accuracy.

There is an obvious intent to either use this as a Sniper’s round, or a competition round, or (more than likely) both.

SIG has bolt actions, semi-autos, and full-autos chambered in this round. In the civilian world it’s marketed as the .277 Fury.

The .277 Fury does to the 6.5CM what the 6.5CM did to the .308. It makes perfect sense to use it in precision rifle applications.

With the tri-metal case, there is no need for a special action. Any rifle or action suitable for the 6.5CM and .308 will work for the .277 Fury/6.8x51mm.

 

[Horsehat]

You’re wrong in that. Look at post #1 again. These are the requirements of the Army AMU for “Match Grade Ammo”. The two bullets selected by the AMU are the Sierra Match King and the Berger Hybrid Hunter, both known for their accuracy.

There is an obvious intent to either use this as a Sniper’s round, or a competition round, or (more than likely) both.

SIG has bolt actions, semi-autos, and full-autos chambered in this round. In the civilian world it’s marketed as the .277 Fury.

The .277 Fury does to the 6.5CM what the 6.5CM did to the .308. It makes perfect sense to use it in a precision rifle applications.

With the tri-metal case, there is no need for a special action. Any rifle or action suitable for the 6.5CM and .308 will work for the .277 Fury/6.8x51mm.

Excellent info, thanks. Any idea what kind of muzzle velocity these will produce?

 

[cmshoot]

Excellent info, thanks. Any idea what kind of muzzle velocity these will produce?

I’ve seen data of 3000fps for 135grn loads, and 2950fps for 140grn loads.

 

[300_whisper]

Still have to ask, WHY?
This is not a sniper round but a ground pounder's shoulder fired round.
Most targets will not be engaged at great distance, therefore no great need for a pill with less drift.
JuSt CuRiOuS...

The big picture why is because the US government created a bogey man with this supposedly “new titanium, ultra lightweight armor” our Chinese near peer friends are running around with. So to combat this we need a round that can penetrate it up to 600 yards.

 

[Dan Muk]

I’ve seen data of 3000fps for 135grn loads, and 2950fps for 140grn loads.

140 grain 270 slugs going 2900fps + do a lot of work at long range and pretty damned efficiently as well!

 

[greg vess]

Extremely interesting information. Thanks for the post.

 

[greg vess]

You’re wrong in that. Look at post #1 again. These are the requirements of the Army AMU for “Match Grade Ammo”. The two bullets selected by the AMU are the Sierra Match King and the Berger Hybrid Hunter, both known for their accuracy.

There is an obvious intent to either use this as a Sniper’s round, or a competition round, or (more than likely) both.

SIG has bolt actions, semi-autos, and full-autos chambered in this round. In the civilian world it’s marketed as the .277 Fury.

The .277 Fury does to the 6.5CM what the 6.5CM did to the .308. It makes perfect sense to use it in precision rifle applications.

With the tri-metal case, there is no need for a special action. Any rifle or action suitable for the 6.5CM and .308 will work for the .277 Fury/6.8x51mm.

Is this going to replace one of the current cartridges in use? The .308 would be the obvious cartridge since added weight would rule out replacing the intermediate round. Or is this just a match/sniper round being put out into circulation? It seems that replacing a Nato round would be a huge undertaking as far as replacing stock piles of the current caliber and swapping out all the rifles currently issued. I haven't really kept up on military arms development lately so I am in the dark on the subject. I had heard a 6.8 diameter round was being tossed around but not to what degree.