More News on the 6.5 Creedmoor: U.S. Military and DHS

[sable tireur]

Ok. Seat them deeper.

O.K. You and I might agree but this flies in the face of the current trend where reloaders do not seat a bullet shank below the neck and shoulder junction. No matter how many times I try to explain this, the majority want to follow the pack and adhere to this 'ideal'. This follows the same stupidity of trying to shoot the heavy for caliber bullets in cartridges which fail to have the horsepower to make them work.

What were these people shooting before this concept became the rule? Websites for reloading data will use the SAAMI OAL even when the longer/heavier bullets are seated below the neck and shoulder junction.

 

[Canadian Bushman]

I think everybody who feels that way outta look into what bullet the military shot before the 175, and why they chose to go that direction.

Perhaps even look into why the U.S. Developed the 30-06 and what caused them to do so.

 

[dfanonymous]

Thank you sir. Like minded individuals we are. I know the 6 or 6.5 CM are awesome cartridges but learning to lob a new round out to 1k and beyond is not desirable for me. Especially when I hold 3/8 MOA with a custom AR-10 and my loads... hell...even my Savage Axis 308 bolt gun shoots 3/4 MOA with 168 MK's. Being prior military I can't imagine being on active duty as a sniper and changing my dope.

You've never gone to the armory To gear up to find your scope has a different serial number? Because apparently POG inspections take priority. That's how the real military works. Inspections. And reorganization of serial numbers.

 

[Satterlee Scott]

LOLO So you haven't tried to load a 208 Amax to 2.80" COAL. Give it a try

 

[Satterlee Scott]

Yup also that a 208 ELD- if loaded to 2.8" COAL to fit in an AR-10 magazine the Ogive will be seated below the neck

 

[Dave Tooley]

Dope changes with every lot of ammo.

Here's what I've never understood. You don't need heavy bullets in a 308. You need well designed bullets. 155-162 gr. bullet
308-155 gr bullet @2900 fps (doable but may require a new powder) @1K yds. come ups 8.6 mils 10 mph wind 2.3 mils
6.5-140 gr. bullet @2700 fps @1K come ups 8.8 mils wind 1.9 mils.
At 600
308 it 's 3.5 and 1.2 for wind
CM it's 3.9 and 1 for wind.
An awful lot of money is being spent for what appears to be not much improvement. And yes I know there were other considerations in play.
At the practical range of 600 yds. the 308 is flatter and the CM has .2 mils less wind drift. Kind of a wash.
Then let's factor in barrel life and the sure to follow maintenance issues.
YMMV

 

[dfanonymous]

Dope changes with every lot of ammo.

Here's what I've never understood. You don't need heavy bullets in a 308. You need well designed bullets. 155-162 gr. bullet
308-155 gr bullet @2900 fps (doable but may require a new powder) @1K yds. come ups 8.6 mils 10 mph wind 2.3 mils
6.5-140 gr. bullet @2700 fps @1K come ups 8.8 mils wind 1.9 mils.
At 600
308 it 's 3.5 and 1.2 for wind
CM it's 3.9 and 1 for wind.
An awful lot of money is being spent for what appears to be not much improvement. And yes I know there were other considerations in play.
At the practical range of 600 yds. the 308 is flatter and the CM has .2 mils less wind drift. Kind of a wash.
Then let's factor in barrel life and the sure to follow maintenance issues.
YMMV

One rarely sees a BC higher when lowering the grain on the same type of bullet. You don't need a higher BC bullet, but it helps.

 

[AFraser]

Dave, That kind of trajectory from a .308 bullet needs a bc of around .520, and I can't find anything over ~.460 on the market, so I wondered what bullet you assumed.

Also, I think the military value the much lower recoil of the 6.5 CM cartridge.
In your example muzzle energy would be 2894 ftlbs for the .308-155, vs 2266 ftlbs for the 6.5-140 = +27% increase.

 

[dfanonymous]

Dave, That kind of trajectory from a .308 bullet needs a bc of around .520, and I can't find anything over ~.460 on the market, so I wondered what bullet you assumed.

Also, I think the military value the much lower recoil of the 6.5 CM cartridge.
In your example muzzle energy would be 2894 ftlbs for the .308-155, vs 2266 ftlbs for the 6.5-140 = +27% increase.

While i agree with a 155 grain not being equal or better than a heavier grain bullet (308), as I put above, I'm also not defending the creedmoor being "superior."

As for the military, ask a 20 to 35 year old SOF dude if they care about recoil.
The 18 to 21 year old infantry man could also careless. The bigger the boom the bigger the smile. As for the brass and bureaucrats, they seldom care about the comfort of the fighting force.

 

[AFraser]

I get your point, but I think the military have a lot of evidence that basic 18-21 year old infantry marksmanship deteriorates quickly with higher recoil. That was part of the original logic behind adopting 5.56mm cartridges.

 

[Dave Tooley]

I was using a BC of .480 for Berger's 155 hybrid and a simple ballistic calculator for a quick comparison with only the bullet changing. My goal was to show how close they were in certain performance categories. With the right design and something around 160 grs. I think the BC could crowd .500 which is more than enough to get to 1K. I shot BIB FB 187's in 1 K comp and never felt like I gave up anything to the bigger bullets. But it doesn't matter, change is on the way.
I get it, less recoil(nobody trains as much as they used to or should), marginally lighter ammo. That will get better when and if hybrid cases become mainstream. It's still a hell of a lot of money to make a change but the industrial base needs some stimulation.

 

[JLM8401]

I read in the ' Military Times ' that they are trying out the 6.8 and getting even better results.

I talked to a guy earlier this year and he told me the same thing. They had "necked up"
the 6.5x47 and 6.5 CM to a .277 bullet and really liked it. This was just for the Gas Guns though. I believe they had a 155'ish bullet.
The guy i talked too worked as a gun builder for the Army at Fort Benning

 

[Dave Tooley]

5 companies are under contract to build prototypes with hybrid ammo. Everyone has their own case design. Some light reading. It will get complicated when it's time to pick a round for the new carbine.
http://soldiersystems.net/2019/01/3...-ppon-for-next-generation-squad-weapons-ngsw/

http://soldiersystems.net/2019/05/23/sofic-19-sig-sauer-exhibits-next-gen-squad-weapons/

 

[dfanonymous]

I get your point, but I think the military have a lot of evidence that basic 18-21 year old infantry marksmanship deteriorates quickly with higher recoil. That was part of the original logic behind adopting 5.56mm cartridges.

It was money, capacity and a lighter rifle that switched the 762 to a 556 as a standard cartridge. The recoil that is talked about is in full auto, which didn't work well in ammo vs hits so they put a 3 rd burst on the A2s. This is before suppressive fire became a doctrine.

The m14 in full auto does suck, so, I'm sure that made sense at the time, but for what the was needed in Vietnam, the m16 was a better option.

The inability to apply fundamental techniques to control recoil is what deteriorates accuracy.

I'm only speaking from experience, I was a team guy. No one ever said, "oh no, I'm not taking the .338lm out today...it's recoil is overpowering and I'm not accurate with it"

Now I can't wait for someone to ask " well the why is socom using the creed now?" "Or why are they making a mk48 in 6.5 creed?"