• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

6.8 replacing 556 and 308?

Why am I yelling! sorry bout that
Nope I believe you are correct. They won't be. I think I read something like 20-28 months before anything is announced and also the consideration is for something between 6.5 and 7mm. 120-130 grain preference and a muzzle velocity of 2800-2900 fps and ability to be effective at 800 yards. Yep, pretty much leaves the 6.8 out of the formula. At least the short 43mm version of it. Now we're back into the 6.5 Creedmoor territory. Wouldn't surprise me a bit
 
There was several online sources that have said the bolt action sniper systems are going to transition from 308 Winchester/7.62x51 to 6.5 Creedmoor. There was also a recent contract awarded to Nightforce for a optic for the Marine sniper rifle. It would provide similar range as a 300 WinMag with less recoil.

The 6.5 Creedmoor is a better caliber than the 308 Winchester by most measurable metrics. I would not be surprised if at some point in the future the 6.5 Creedmoor finds its way into automatic and belt fed systems, at least for small specialized units like SOCOM or similar. It will never go military wide as long as we maintain our place in NATO.

I know that there have been testing involving the 300 Blackout as well as limited fielding among specialized units.

Another recent caliber to get some traction is the 6x35 KAC cartridge. It is a 221 Fireball necked up to 6mm. It provides similar energy as the 5.56 but does so with less muzzle blast and less recoil with shorter barrels that are loud and obnoxious in 5.56.

There is also a push to use 338 Norma Mag in belt fed machine guns to give them more range compared to a typical 7.62x51 belt fed. I know there has been some serious testing in it but like all the others it will have limited use as long as we are held to the NATO standard.
 
Insider info for those that keep guessing.... 6.8x51 aka 270-308. This is the top contender as of now. 125-130 grain bullet around 2900 fps in 16" bbl. Bullets all govt designed...nothing close commercially. Brass and steel case. 20% lighter than 7.62x51 ammo. They are hell bent on using 6.8 for whatever reason and Zero chance it will be 6.8 SPC or therabouts..
 
Insider info for those that keep guessing.... 6.8x51 aka 270-308. This is the top contender as of now. 125-130 grain bullet around 2900 fps in 16" bbl. Bullets all govt designed...nothing close commercially. Brass and steel case. 20% lighter than 7.62x51 ammo. They are hell bent on using 6.8 for whatever reason and Zero chance it will be 6.8 SPC or therabouts..
There's polymer cases in the mix also. 6.8 is supposed to be the minimum diameter needed to build the special purpose bullets they want.
 
it sounds like BS on the militarys part. 99% of the soldiers can't find a neutral colored target at 800 yards. The appropriate solution, according this once Army Ranger (3 tours in RVN) is more live fire training with what we have.
 
6.8 is supposed to be the minimum diameter needed to build the special purpose bullets they want.

The British War Office Ideal Calibre Panel of the late 1940s whose work led to the 'intermediate' 7X43mm (280/30 British) assault rifle cartridge that was the 7.62X51mm T65-E3's main competitor in the 1950s NATO arms trials identified 0.277 (6.8mm) as the optimal calibre in this cartridge class for its mix of SD, potential BC and MV plus retained terminal energy. For various practical reasons including likely being easier to make tracer and AP, the marginally larger 284 calibre was eventually selected. I imagine too that this decision was swayed by FN having an already designed 284 139gn FMJBT bullet available off the shelf with impressive external ballistics for the period.

IIRC, John Pedersen identified the '270' calibre as one of his possible calibres for his prototype 1920s self-loading infantry rifle, but as with the Brits a generation later eventually opted for 7mm in his prototypes submitted to the US Army for evaluation
 
Last edited:
There's polymer cases in the mix also. 6.8 is supposed to be the minimum diameter needed to build the special purpose bullets they want.
True on both but caliber not to exceed 7mm and from what I'm told (as of now) there aren't any 7mm cartridges in the running. Funny...we could have just gone the route of the British 280 from the 50's and been GTG.
 
Funny...we could have just gone the route of the British 280 from the 50's and been GTG.

Yes, it was a shame that the 280/30 died, an opportunity lost. It must have a little more capacity than the 7mm BR with a 0.2-inch longer case, but some of that offset by greater case body taper. In AI form with strong modern small primer brass it would be an interesting competition round.
 
Going back to basics, whether the US forces - which in turns means NATO countries' forces - really do finally intend to adopt something significantly larger and longer than the 5.56 has to be open to question. This sort of story resurfaces every few years, and what have seen to date? The 6.8mm SPC that wasn't a massive success. Given too that the US has just procured a vast number of M4 carbines making it the standard infantry individual weapon, and with a life of 20 + years ahead of them, the replacement costs would be astronomical. Other NATO governments' appetites for any military expenditure is with one or two exceptions non-existent and most aren't even meeting the minimum financial commitments.

Adopting 5.56 has made all current weapons platforms exceptionally restricted in cartridge terms - 2.26" COAL and small case / case-head diameters. When Stoner built his prototype ARs around the off the shelf 222 Rem he never envisaged it leading to a similar design becoming the West's primary battle cartridge. So the conundrum remains and stymies change again and again - ballistics improvements need larger cartridges; existing platforms can't handle anything much bigger than the 5.56; nobody can afford the vast sums required to start again with a fresh platform.

The 1950s saw the near across the board obsolescence of existing 1945 era rifles, the urgent need for NATO standardisation, and the huge threat that a several million strong Red Army sitting on the West's doorstep and ultimately directed by a dangerous and aggressive psychopath in the form of Josef Stalin made the case for urgent change unassailable. The US involvement in South East Asia a generation later and the manifest unsuitability of the 7.62 M14 for the kind of wars and terrains being fought over made the case for the 5.56 and M16. Are there any such pressing needs today that react to existential threats to Western nations' existence? Most western politicians would answer 'No' especially if they had to cut other pet projects or sectors' funding to spend more on military equipment.

(And on what is a very un-sexy project too as far as most politicians are concerned. These are men and women who have demonised the very concept of the 'assault rifle' in their public appearances and utterances for many years now. Frankly if they could uninvent the whole concept and the StG44, AKs, M16 etc has never appeared they'd be delighted! Whole - and very influential western NGOs have dedicated themselves and their public fundraising campaigns to stopping the improvement and spread of this weapon type giving it as much attention as winding down the numbers of nuclear weapons and major strategic platforms received a generation ago. The liberal media hate all military expenditure and weapons systems, but have also made excellent careers and livings out of demonising the feared and hated 'assault rifle'.) ......... et cetera; et cetera!

Special ops / sniper limited issue platforms are another matter, but the numbers involved are small beer for all involved in justifying the R&D, retooling etc. If we do see a significantly ballistically enhanced 270 or 7mm come into limited use and prove itself, it does strengthen the case for wholesale change though.
 
As stated right now the 5.56 is not going away anytime soon. Support and rear echelon types will still carry the 5.56. Combat troops will get upgraded SAW's, MG's and carbines.
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
165,627
Messages
2,199,807
Members
79,014
Latest member
Stanley Caruthers
Back
Top