I understand your point, but in FN SCAR 20, there are surprisingly folk reporting many problems with these in 6.5 Creedmoor on factory ammo no reloads. In the end given that 6.5CM is not operating at any higher pressures both .308 and 6.5CM use the same primers and same case head, so can't quite see why the gun would need a specific 6.5CM bolt. 

at 12:00 they actually say they measured all the specs on firing pin and bolt hole etc and its all in specs.

https://www.youtube.com/watch?v=eUTLPwoZSdE

Interesting digital daysight ,this is definetly where we are heading if the energy consumption can be tackled.

https://www.youtube.com/watch?v=FWmy7Bi25lY

EmericD said:

I really doubt that a "standard pressure" 6.8 mm will do anything the 6.5 mm Creed can't, and you can find now "tactical / precision" loads for the 6.5 mm that you could only expect to see after 2025 for the 6.8 mm.

I just did a brief search, and I could not find any 6.5 CM ammo now available that looks like it would meet military requirements.

There is no EPR, lead free FMJ, AP, Tracer, Blank.  All still have to be developed, so 6.5 CM has no advantage over 6.8 in this regard.

Lead core FMJ is marketed, but it lacks a crimped primer, and appears to not have waterproof sealing of the primer and case neck.

stancrist said:

I just did a brief search, and I could not find any 6.5 CM ammo now available that looks like it would meet military requirements. There is no EPR, lead free FMJ, AP, Tracer, Blank.  All still have to be developed, so 6.5 CM has no advantage over 6.8 in this regard.

Sorry, but SOCOM (or Special Forces in general) don't use blank ammo, nor EPR, nor lead-free FMJs. Even tracers are barely needed, because when you run suppressed you don't really want tracers to show where you are.

You have tons of tactical / OTM loads available in 6.5 mm CM from Lapua, Berger, Hornady with "match like" accuracy... Lapua is also loading the Naturalis & Mega bullets that are good bullets to shoot thru glass, and specialized company like Extreme Precision are providing AP and APFI (Armor Piercing Flash Incendiary) ammo.

SOCOM choose the 6.5 mm CM instead of the 260 Remington (which was the first choice of the Delta Force) because of the availability of Match ammo designed for PRS use, when the commercial loads of 260 Remington were more focused towards hunting.

schnuersi said:

I did not look at the dimension at all. Just the performance.

If the continuous use of the same weapons is desiered its obviously not the first choice.

Heh, heh.  I'd say that "not the first choice" is an extreme understatement.  The US just spent a lot of time and money developing the XM5 and XM250.  A caliber change (to 6.5 CM, for example) that requires only a barrel swap would be one thing.  But changing to a longer, fatter cartridge like 6.5x55 would pretty much require starting over from scratch, to develop new guns, mags, etc.

schnuersi said:

The Swedish military used 6,5x55 in  the FN Mag wich they later converted to 7,62x51. The ballistics of the 6,5x55 are really good and its an old cartidge. Applying some modern tech its performance should get even better.

I imagine that's true.  It just doesn't seem (to me) that it would be worth the effort and expense.

Conversion of FN MAG variants should be easy, with just a barrel (and bolt?) change.  That's assuming existing links are compatible with the 6.5x55 case taper and diameter. 

But it would be necessary to design and develop completely new rifles with longer receivers.  And those rifles would need new magazines, with considerable curvature, like those of the Swedish BAR.

schnuersi said:

I just don't get what 6,8 does that non of the alternatives does.

I don't know how that could be determined without doing comparative testing of 6.8 SIG versus the alternatives.

Only because no one buys it ,the moment someone orders 1mio rounds of ammo they can be made   as many of the components are already available off the shelf. If you look at ammo sales today 6.5Creedmoor offerings are second only to .308win ,223rem ,30-06, those FMJ from S&B retail at similar pricepoint as .308 FMJ

quick look at Midways USA  offer , number of different lines/models/brands :

170x .308win 

135x  .223rem 

115x 30-06

 93x  6.5 Creedmoor 

66x .300Blk

20x .260Rem

3x 6ARC

1x 6.8x51 - 277Fury

Lapua now also offers 146 grain AP bullet AP570 , lead-free is also non issue just about every manufacturer offers it , 

Indeed my suspicion on 6,5 CM vs ,260 Rem choice was down to ammo availabiltiy ,as .260Rem has a sparse offering in comparison to Creedmoor. But .260Rem still seems to have some game as some of European SF units picked .260 DMR /SSR rifles over 6.5CM and at least Lapua is marketing 260 also as a tactical offering.

S&B lead free.

''Air lock'' sealed cartridges option on all their hunting calibers including 6.5 Creedmoor

mpopenker said:

       schnuersi said: I just don't get what 6,8 does that non of the alternatives does.

Money and PR for persons and companies involved

American defense business at its best, where money rule over everything.

  The caliber was specified by the Army.  American defense business had no say in the matter.

EmericD said:

Sorry, but SOCOM (or Special Forces in general) don't use blank ammo, nor EPR, nor lead-free FMJs. Even tracers are barely needed, because when you run suppressed you don't really want tracers to show where you are.

Sorry, but the discussion is not about SOCOM requirements.  It is about 6.5 CM and other 6.5 cartridges as alternatives to 6.8x51 SIG for NGSW use. 

That means EPR, AP, Tracer, Blank ammo would, in fact, be necessary.

Mr. T (MrT4) said:

I understand your point, but in FN SCAR 20, there are surprisingly folk reporting many problems with these in 6.5 Creedmoor on factory ammo no reloads. 

And some folks using commercial .223 ammo in AR-15s (or commercial .30-06 in the M1 Garand) have experienced slam-fires...

When I found parts of primers into the mechanism of a rifle, my first thought is not to check the rifle, but to select another load.

stancrist said:

Sorry, but the discussion is not about SOCOM requirements.  It is about 6.5 CM and other 6.5 cartridges as alternatives to 6.8x51 SIG for NGSW use.  That means EPR, AP, Tracer, Blank ammo would, in fact, be necessary.

Well, unless you can load the government-issued 6.8 mm NGSW bullet in a 6.5 mm Creedmoor (or other 6.5 mm cartridge), there is nothing to discuss.

EmericD said:

Well, unless you can load the government-issued 6.8 mm NGSW bullet in a 6.5 mm Creedmoor (or other 6.5 mm cartridge), there is nothing to discuss.

Clearly you are mistaken, because half a dozen members have been discussing it.