SIG Sauer’s updated M7 reflects the U.S. Army’s Product Improvement Effort, pairing a shorter barrel and revised suppressor with the ballistic advantages of 6.8x51mm. Over the last 60 years, the M16 has evolved to the current versions of the M4; it’ll be cool to see how the M7 continues to improve over the next few decades.
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A More Compact M7 for Army Use
SIG Sauer continues refining the M7 rifle as part of the Army’s Product Improvement Effort. The latest configuration focuses on overall size, weight, and handling rather than altering the rifle’s mission.
The most visible change is the barrel length. The updated M7 now uses an 11-inch barrel. Despite that reduction, the rifle still produces muzzle velocities exceeding 3,000 feet per second with 6.8x51mm ammunition. That level of performance remains above what typical 5.56x45mm service rifles deliver, even with longer barrels.
Shortening the barrel reduces the rifle’s overall length and improves maneuverability. That matters for mounted operations, CQB environments, and working inside vehicles or confined structures, where longer rifles can be slow and awkward.
Shorter and Wider Suppressor Design
The revised M7 also features a redesigned suppressor. This version is shorter and wider than earlier suppressor configurations used with the rifle. Reducing suppressor length cuts down on added forward length while still meeting Army suppression requirements.
A shorter muzzle length improves balance and handling, especially in tight corridors and urban interiors. It also reduces the amount of weight acting as leverage at the front of the rifle during movement and transitions.
Stock Changes and Weight Reduction
The updated M7 moves to a non-folding stock. Removing the folding mechanism eliminates extra components and reduces overall weight. It also simplifies the stock assembly and aligns with the Army’s emphasis on durability and consistency rather than compact storage. SIG also reduced the mass in the receiver to make it lighter. Overall, they shaved about a pound off the original.
These updates reflect incremental changes driven by field use and formal feedback under the Product Improvement Effort, not a full redesign of the weapon.
6.8x51mm Ballistics vs. 5.56x45mm
The M7 remains built around the 6.8x51mm cartridge, which continues to separate it from legacy rifles. Compared to 5.56x45mm NATO, 6.8x51mm fires heavier bullets at higher velocities and retains significantly more energy at distance.
Standard 5.56mm loads typically launch 55- to 77-grain projectiles at roughly 2,700 to 3,000 fps from longer barrels. Velocity drops quickly as barrel length shortens. Energy loss becomes more pronounced past intermediate ranges, and wind drift increases.
By contrast, 6.8x51mm uses heavier projectiles — 113-grain and 140-grain — that maintain velocity and energy farther downrange. The result is a flatter trajectory at extended distances, better resistance to wind drift, and substantially higher retained energy. Those characteristics directly support the Army’s requirement for improved performance through intermediate barriers and against modern threats.
Even from an 11-inch barrel, the M7 delivers external and terminal ballistics that 5.56mm platforms cannot replicate at comparable lengths.
Military Grade
SIG Sauer’s M7 is a military system developed specifically for the U.S. Army. Its refinements will eventually trickle down to the consumer rifle, the MCX-Spear.
The updated M7 demonstrates how the Army is refining the platform in service: shortening it, simplifying it, and adjusting it to better suit operational use without changing the rifle’s role.
GunsAmerica will keep you apprised of future revisions to the M7 platform.
M7 vs. M4A1 – Service Rifle Comparison
| Feature | SIG Sauer M7 | M4A1 |
|---|---|---|
| Caliber | 6.8x51mm | 5.56x45mm NATO |
| Barrel Length | 11 inches | 14.5 inches |
| Operating Role | U.S. Army service rifle (NGSW) | U.S. Army service carbine |
| Typical Bullet Weight | Heavier projectiles | 55–77 grains |
| Muzzle Velocity | Over 3,000 fps (11″ barrel) | Limited by a lighter projectile |
| Trajectory | Flatter at extended range | Steeper drop at longer distances |
| Wind Drift | Reduced at distance | More affected by wind |
| Retained Energy | Significantly higher at range | Drops off more quickly |
| Barrier Performance | Improved | Limited by lighter projectile |
| Stock Type | Collapsible | Collapsible |
| Suppressor Use | Designed for routine suppressed fire | Suppressor-capable, not standard |
| Availability | Military only | Military and civilian variants |
SIG Sauer M7 Specs
- Caliber: 6.8x51mm
- Barrel Length: 11 inches
- Muzzle Velocity: Over 3,000 fps (6.8x51mm)
- Suppressor: Shorter, wider profile (Army configuration)
- Stock: Fixed, non-folding
- Role: U.S. Army service rifle
- Commercial Availability: Not available to consumers
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Levi is an avid hunter, and an increasingly avid shooter. He strives to make delicious and simple recipes from the game he kills. He makes a living as a professional photographer and writer. Check out his work.
Wonder if it comes standard with the patented leg-shooting feature?
More grift from Sig with the full support of the Army. Would love to have the AG investigate this procurement along with the specifics of the M17 procurement. Some Army civilians and officers have house payments made by Sig..
From what I understand from soldiers using this weapon in the field is it lacks in accuracy, often in the 2-3 MOA range with frequent fliers. The heavier, faster projectile provides little advantage on targets that can’t be hit. To me, any article that expounds on the virtues of a rifle without a thourough test of accuracy is remiss.
In addition to concerns of the previous comments (i.e.: Barrel Length/Life), What is the weight of this rifle? It appears to not be able to accommodate a Bayonet ?!
Compared to 5.56x45mm NATO, 6.8x51mm fires heavier bullets at higher velocities and retains significantly more energy at distance.
So does the 6.5 Grendel, a much smaller lighter round that uses the current AR-15 receiver.
Compared to 5.56x45mm NATO, 6.8x51mm fires heavier bullets at higher velocities and retains significantly more energy at distance.
So does the 6.5 Grendel, a much smaller libhter round that uses the current AR-15 receiver.
oops, “lighter”.
Right, but that doesn’t satisfy the Sig-Army grift requirement.
I’ve never been a fan of selling military hardware to other countries, NATO included, you end up fighting you own hardware and equipment.
I’m really against buying and equipping our warfights with weapons of any kind from a foreign owned company’s
We should produce are own. For our own consumption.
We just watched on the news, a C-130 with another nations marking, land in Greenland, unload their soldiers in defiance of the USA.
The reason doesn’t matter on this specific point, just the fact our plane they own, was used.
Embarrassing and infuriating as a honorably discharged service member.
The 6.8×51 should not be compared to the 5.56×41. It is more like the 7.62×51 in rifle and cartridge weight and that would be a far better cartridge to be used in comparison.
I have no problem with the US Military switching to a cartridge with better performance as I believe the AR 10 and clones are great rifles with much better terminal ballistics at range than the M4A1 but there is a downside as the rifle and cartridge comes with a significant weight disadvantage over the current M4A1.
Maybe the 6.8 is a good compromise between the 5.56 and the 7.62 or maybe it is simply another change for the sake of change caliber, but either way I am a bit concerned if this is the best place for the US Military to be spending their allotted funds.
This is, has, and will continue to be a huge boondoggle ultimately at the expense of our troops lives. The sugar-coating and fluff are absolutely ridiculous. This is a farce of a firearm and a logistical nightmare that has even yet to see real application and the difficulties it will cause have already been apparent. Continuing to “fine tune” it is pointless. Unless, that is, you have political leverage to keep squeezing money from a government contract.
BLUF: I’ve been skeptical about this rifle program since I first learned a few of its design parameters. I sincerely hope I’m being far too pessimistic, and that this rifle turns out to be the greatest of all time. If it does, I’ll be happy to confess that I was an idiot.
So, I have doubts–serious ones:
1. Didn’t take long for soldiers to voice their (thoroughly predictable) objection to the brutal weight of this beast.
2. I wonder when we’ll learn definitively that 80K PSI chamber pressure is (predictably) beating both weapons and firers to pieces?
3. And that the complicated, experimental cartridge case design is (predictably) experiencing major problems in manufacture and use?
4. Already shortening the barrel on a rifle…whose primary design impetus was a response to the long-range fire of theancient M1891 Mosin-Nagant and its 7.62x54R cartridge in the mountainous wastes of Afghanistan. Now we have a long-range rifle…with an 11-inch barrel? How much of a reduction in MV? What’s the impact of the change on suppressor life, gas & recoil system, bullet trajectory & sighting systems, terminal ballistic performance? Impact on barrel life, with less barrel mass to absorb the heat generated by firing an 80K PSI round?
5. Can we keep enough replacement barrels and suppressors, armorers, tools, and spare rifles on-hand to sustain rifle companies in combat? The contract requirement was 10-12K rounds barrel life, but I’ve read that we may be experiencing erosion problems at the 2K mark, which seems likely on its face. I can’t imagine suppressors last long at these pressures, temps, and velocities–are we burdening troops and units with toting a ton of spares?
I suspect this rifle program will wind up being declared a “high-tech, test bed experiment,” making us wish we’d simply kept the M4-series carbines, and re-issued several M16A2’s per platoon. Or refurbed NM M-14s. Or just dusted off some M-1903s with M-1 .30 caliber (heavy) ball, long-range ammo–the boat-tailed 174g stuff that overmatched the Army’s rifle range safety fans in the 1920s and also proved too powerful for the M-1 Garand…! Hey, a century-old solution in response to a century-old threat!
I agree with everything you said until you got ridiculous and started mentioning the old obsolete military rifles. The M14 was a failure on many counts, its stock allowed too much muzzle rise and even worse it was a jam a matic when the slightest contaminates entered the action much as the M1 rifle also did. Both rifles had actions open to the elements, even dusting off the FAL would have been a better rifle both back in the day and in the present.
Forgotten Weapons stomped an M14 into the mud and it jammed tight after only 1 shot. Even the much criticized M16 when it was clean and the dust cover closed fired off the entire magazine after being stomped in the mud and most shocking was that the much worshiped AK47 jammed up on the 2nd shot.
I predict this new disaster and Franken-creation of the “slide rule technicians” will soon become the biggest boondoggle failure of any of the U.S. Military rifles ever adopted and it will last as long as a snowball in hades. The biggest laugh is the 11 inch barrel, surely the idea came from an arms designer high on drugs.
Not “getting ridiculous.” I was pointing out that even such half-assed “solutions” would turn out to be preferable–because they’d be dirt cheap, quick, and easy–to the ridiculously expensive, ill-conceived M-7 monstrosity which will suck years out of Army rifle development in the process of trying to make its sow’s ears into a silk purse.
Everything talked about seems good, but i have a few questions.
With the much higher chamber pressures, what is the estimated life of the system?
How many rounds will they be able to put into a magazine and expect dependability?
How many rounds would one man be carrying with them?
Basic load is cut to 200 rounds or less. The SAW version cuts load by a third also. Whereas an “expensive” 5.56 round is fifty cents, word is these are in the $3-5 per round area. Just another Unicorn some desk general was convinced could replace all the other weapons in use, be a standard, etc.
Shortening the barrel speeds up barrel erosion is even faster. And the field reports say that by 1,000-1,200 rounds, accuracy falls to 6.0 MOA, making an AK look like a sniper rifle. SIG can polish this turd as much as it wants, it will always be a turd!
I’ll bet it has a lot more recoil now, which will make follow-up shots slower. But that will help make the ammo last, with lower capacity mags.
Levi… This is your worst article to date. You should be particularly embarrassed that you don’t know the muzzle velocity of the 5.56 x 45 mm M855 round which is what the military uses. So NO, the 11 inch barrel on the M7 muzzle velocity does not exceed the 5.56. Even Siri knew the answer to that and she’s an idiot. Even mentioning the energy of the 6.8 versus the 5.56 is ignorant and juvenile. Gee… who would’ve thought a bigger caliber with more propellant would deliver more energy?
And if you’re gonna give us all this information about all these cuts SIG is making… Why don’t you throw some of those numbers out there? What a waste of my time!
What does the rifle weigh? Without optics, laser and suppressor and then as carried, with optics, laser and suppressor?