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.

US military is an integral part of the game

Specifications for the SPIW, ACR, OICW, Bradley, Zumwalt, and myriad of other failed systems were specified by the military

I just wonder how many of generals and colonels who formulated those requirements or downselected contractors ended up in the advisory boards of said companies after their honorable retirement from active duty.

stancrist said:

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

Discussing how to use the government designed XM1186 (which is the starting point of the NGSW program) in a 6.5 mm cartridge? I should have missed something, for sure!

What I read is discussions about why SOCOM resumed it's 6.5 mm Creedmoor program, instead of following the path of the Army's NGSW, hence the fact that we are also talking about SOCOM requirements, and not NGSW requirements...

EmericD said:

What I read is discussions about why SOCOM resumed it's 6.5 mm Creedmoor program, instead of following the path of the Army's NGSW, hence the fact that we are also talking about SOCOM requirements, and not NGSW requirements...

Perhaps you missed these posts?

Msg 2699

• US SOCOM has two current programmes to field weapons in 6.5x49 mm Creedmoor ; one is the MRGG the other is a LMG
• The above initiatives could be a hedge in case NGSW fails to live up to expectations

Msg 2701

6.5 CM is a less capable caliber than 6.8x51, and 6.5 CM weapons are as big and heavy (or heavier?) as the 6.8x51 guns.

Msg 2712

US SOCOM, after seeing from the insight all the greatness of the 6.8x51 mm, decided to resume its 6.5 mm Creedmoor program.

Msg 2713

That is what allways puzzeled me. The 6,5 Creedmore allready does what the 6,8x51 is supposed to do. Its a established and mature design. Even if the Creedmore is not an option the 6,5x55 Swedish does the same as well. The 6,8x51 tp me allways seems a case of reinventing the wheel.

Msg 2718

Perhaps.  I think it would depend upon how much difference there is in performance.  And if one wants to go for an existing cartridge, 6.5x55 seems to me like a bad choice.

Msg 2719

6.5x55 is outdated  newer 6.5 cartriges more than emulate its performance in oal suitable for existing 308 magazines. 6.8x51 stuffed magnum performance in a case that fits the .308 mags. But high pressure is hardly free lunch.

Msg 2720

As a replacement for 5.56, 6.8 seems pretty nuts. But as a replacement for 7.62 or 6.5C,it seems much more compelling. There weapon and ammo weight is essentially identical but with much better ballistic performance for 6.8.

Msg 2724

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

Msg 2730

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.