Home Forums Hunting & Shooting Ask The Gunwriters U.S. Army moves to 6.8X51

I apologize if this has been asked before but what does everyone think about the new 6.8X51 cartridge that the U.S. Army is moving to. Will this be the new hotness in the sporting rifle world?

3000 fps out of a 16 inch barrel for a 140 gr bullet sounds very impressive. What would be the potential speed out of a 22 inch sporting rifle barrel? Maybe 3300 fps if you factor in approx 50 fps per inch of barrel.

External ballistics should be very good as well with high BC bullets.

Potential downsides for this would be the 80,000 PSI pressures that the Hybrid case is designed for. Would this be a reloading nightmare? What about barrel life? Would this round be insanely loud without a suppressor attached? What about factory cost per round given the hybrid construction of the case?

It seems odd that after 60 years of convincing the NATO allies of the benefits of the intermediate rifle cartridge that there is a shift back toward the full power cartridge. Seems like a step backwards.

Wait I thought the Army was adopting the 6.8??? Now they are adopting a 6.5x51 so uh a 260..

Wouldn't this be the 260 Remington? Only loaded to higher pressure and with a thick case.

Cartridge collector says this:
This was an experimental cartridge by Belgium for the Swedish ‘MAG’ machine gun. It was based on the standard 7.62x51 NATO case.

Link?

As far as I have seen, it is the 6.8 x 51:

https://blog.refactortactical.com/blog/277-sig-fury-ngsw

80,000 PSI seems like a big shift in pressure and a lot of sporting rifles won't be able to handle it.

Sorry - you are right - It is 6.8X51 - Corrected my Original Post

Probably a devastating cartridge. On the minus side, short barrel life, extremely loud report, as mentioned. I believe that all affected rifles will have suppressors, and for good reason.

An all brass cartridge case, designed for more traditional pressures, is also available.

The 277-08 is reborn!

Hmmm...

So, after about 100 years the .gov circles back to .276.

Recall the .276 Pedersen?

The 6.8 x 51 dimensions are very similar to the .270 Redding. Similar: body taper, shoulder diameter, 30 degree shoulder, case length etc. Out of a 22" barrel the brass cased .270 Redding gets around 2950 fps with a 140 grain projectile using H4350.

Garand thumb just did a video on the rifle.

Isn't that an AR10 size rifle? Seems strange that a standard AR15 size gun wasn't selected with a 6mm or 6.5mm cartridge.

w/ .270 Win. ballistics.

While a nice piece of kit for an assault rifle or SAW, Underwhelming as a hunting round, as the .270 Win. has already plowed that road.




GR

The .276 Pedersen was really a 7mm x 51 from what I understand. They measured the bore across the rifling rather than the grooves, I expect. There's nothing wrong with the .270 Win as a hunting round. Getting close to .270 Win ballistics in a short action is desirable by people such as myself.

It is indeed. Stripped it is 9.3 lbs. Add another 2.5 lbs for the new smart optic plus add on a laser designator and full 20 round mag and you're probably looking at 13 plus lbs.

Anyone know why the Army picked 6.8 instead of 6.5?

I read something about the bore size being optimal from their tests. Don't forget that you lose a little velocity for the same bullet weight when you drop down in bore size.

So, a soldiers basic load is shrinking or not?

Historically the US research and development, procurement, outright f---kery at Springfield Armory and Arsenal, and political shenanigans has just been short of criminal. The poor grunts have been behind the curve of modern small arms, compared with other countries, forever. The most glaring being the sacred cow of the trapdoor, basically a muzzleloader with a breech installed. (ask Custer's men, ask Spanish Amer. war troops with trapdoors against Mausers) Then comes the AR 15, which couldn't be peddled because of it's issues, Colt bought it, bought a bunch of congressmen and generals and sent it into combat with documented failures to function. Grunts died, Jesus wept. Stoner's kick ass AR10 would have worked, but he didn't buy any congressmen. Oh, the Stoner...we can't carry a big enough ammo load....sound like a supply problem to me. M16 as developed is a fine weapon now, but in urban combat it won't punch through cars, in long range engagements in the desert it was lame. Good thing the grunts in the sand didn't have to come up against disciplined units with FN FALs instead of 'AK almost .30-30's'. I think the testing and procurement processes of the US is so corrupt, that if the grunts do get a good weapon, it will be mostly by luck. I know nothing of weapon design, but 80k chamber pressure sounds like an opportunity for Murphy's Law to apply itself. We shall see.

Isn't that a 6.8x51 - the .277 caliber bullet?

Not to worry jfb will ship them all to biden