gatnerd

Military Guns and Ammunition

Hosted by gatnerd

This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

  • 3357
    MEMBERS
  • 191126
    MESSAGES
  • 2
    POSTS TODAY

Discussions

NGSW Phase 2 Consolidation and info   Small Arms <20mm

Started 30/8/19 by gatnerd; 547394 views.
EmericD

From: EmericD

22/5/22

gatnerd said:

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. Ii wonder what SF saw that made them want to go back to 6.5?

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. Seems interesting that every time there is a demo with the 6.8 mm, the bullet loaded is a Nosler Accubond, which is neither a FMJ, nor and OTM, but a truly hunting bullet with an impressive C7 of 0.298 for the 150 gr LR version.

The "+P++" 6.8 mm have much better ballistics than the 6.5 mm Creed, but also have drawbacks in terms of recoil, safety, cost, availability & weapon service life.

Mr. T (MrT4)

From: Mr. T (MrT4)

22/5/22

Can't put a finger on it where it went wrong but 6.5CM is quite temperamental. Calibers like .223Rem ,308win are superb designs in their own right , accurate more than folks can dream of , have good burn so can be loaded to very low ES SD numbers , all the popular 'competitive' calibers like 6BR , 6.5x47 , 284win , 6XC can easily be loaded for superb accuracy and consistency (ES SD), 6.5creedmoor is not even close  which is kinda surprising considering how popular it is now , 6.5CM cases are availibile in both small and large primer variants and it doesn't seems to cure the lack of consistency even with absolute premium components. Not to mention there are plenty of instances where 6.5CM has issues in some semi autos like FN SCAR that has issues with pierced primers and failures to  feed a cartridge that was supposedly drop-in fit with only barrel change.

260 rem issue over 6.5creedmoor is that the longest bullets like  147g Honady ELD-M need to be seated deep to fit magazine oal. But in many ways 147 an 150g class bullets are too heavy for these cartridges to achieve high MV. You are limited to 2750 FPS or something out of 26' barrels , if you cut barrel down to 20 or 16  (16'' at 2350fps with 147eld)its far to slow for practical use . 260 rem like 264 USA is well shaped for feeding in full auto  guns.

.260rem  and 6.5CM  , bullet in between is extreme heavy weight in 6.5mm caliber  156g Berger Eol ,that is best left to long action cartridges.

schnuersi

From: schnuersi

22/5/22

stancrist said:

And if one wants to go for an existing cartridge, 6.5x55 seems to me like a bad choice. As shown in the pic below, 6.5x55 is too long to be used in rifles designed for 7.62x51.

True. 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.
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.
7,62x51 also can be hot loaded.
I just don't get what 6,8 does that non of the alternatives does.

mpopenker

From: mpopenker

22/5/22

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. Fruitless and endless R&D on budget money is a preferred sport of most big- and medium-size contractors who can buy themselves enough pawns from Congress for support

EmericD

From: EmericD

22/5/22

Mr. T (MrT4) said:

Not to mention there are plenty of instances where 6.5CM has issues in some semi autos like FN SCAR that has issues with pierced primers and failures to  feed a cartridge that was supposedly drop-in fit with only barrel change.

It could also happen to .308 / 7.62 x 51 mm weapon, where 168 gr match loads developped for bolt-action rifle suffered the same fate (pierced primers & FtF)  when used in the HK417... so I won't take this kind of bad experience as a case against the 6.5 mm CM.

Mr. T (MrT4)

From: Mr. T (MrT4)

22/5/22

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

stancrist

From: stancrist

22/5/22

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.

EmericD

From: EmericD

22/5/22

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.

stancrist

From: stancrist

22/5/22

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.

Mr. T (MrT4)

From: Mr. T (MrT4)

22/5/22

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

TOP