Boy it's refreshing to read knowledgeable information from someone who knows what a cartridge is instead of a "caliber". Thank you Ulysses! I bet I know where you got your training.

Guess that's why he was endorsed by NRA, GOA, NSSF,
TSRA, etc. etc……?

I love firing the M17

Not about Biden. I apologize that you misunderstood. My post was an opinion about the poster.

BassCowboy33 said:

---

techno-ag said:

---

https://trendydigests.com/2024/04/25/the-dawn-of-the-xm7-u-s-armys-transition-from-the-legendary-m16-series/

Quote:

---

After over five decades of faithful service, the M16 series, an icon of American military might and a direct descendant of the AR-15 designed by Eugene Stoner will be succeeded by Sig Sauer's advanced XM7 rifle. The M16, first introduced in 1964, has been the most-produced 5.56x45mm weapon, marking a significant chapter in the annals of U.S. military history. The latest variant, the M16A4, known for its three-round burst feature, will soon yield to the cutting-edge design of the XM7, a testament to the relentless pursuit of small arms excellence.
…
Sig Sauer's XM7 and XM250 promise a significant capability increase over their predecessors, firing a common 6.8mm ammunition that delivers greater effectiveness against current and emergent threats. The new round, an intermediate caliber, outperforms both the 5.56mm and 7.62mm in terms of accuracy and power, especially at extended ranges - a critical factor in modern combat scenarios where adversaries have improved their body armor.

---

So it looks like a heavier caliber was the impetus behind this change. Better stopping power, better body armor penetration.

Looks like Sig is the main supplier of military handguns too. They replaced Beretta with the Sig M17 9mm.

Weapons procurement, at this level anyway, appears to be free of some of the turmoil we see elsewhere. Unless there's some political stuff not hitting the news. Any of you guys with military connections know anything?

---

By the time I went in in '10, the M16 was already on the outs. I didn't even know it was still being used by any of the branches. The M4 carbine is the superior weapon.

---

The M4 is still based on the M16 though. It's basically a carbine version of the platform as I understand it.

techno-ag said:

---

BassCowboy33 said:

---

techno-ag said:

---

https://trendydigests.com/2024/04/25/the-dawn-of-the-xm7-u-s-armys-transition-from-the-legendary-m16-series/

Quote:

---

After over five decades of faithful service, the M16 series, an icon of American military might and a direct descendant of the AR-15 designed by Eugene Stoner will be succeeded by Sig Sauer's advanced XM7 rifle. The M16, first introduced in 1964, has been the most-produced 5.56x45mm weapon, marking a significant chapter in the annals of U.S. military history. The latest variant, the M16A4, known for its three-round burst feature, will soon yield to the cutting-edge design of the XM7, a testament to the relentless pursuit of small arms excellence.
…
Sig Sauer's XM7 and XM250 promise a significant capability increase over their predecessors, firing a common 6.8mm ammunition that delivers greater effectiveness against current and emergent threats. The new round, an intermediate caliber, outperforms both the 5.56mm and 7.62mm in terms of accuracy and power, especially at extended ranges - a critical factor in modern combat scenarios where adversaries have improved their body armor.

---

So it looks like a heavier caliber was the impetus behind this change. Better stopping power, better body armor penetration.

Looks like Sig is the main supplier of military handguns too. They replaced Beretta with the Sig M17 9mm.

Weapons procurement, at this level anyway, appears to be free of some of the turmoil we see elsewhere. Unless there's some political stuff not hitting the news. Any of you guys with military connections know anything?

---

By the time I went in in '10, the M16 was already on the outs. I didn't even know it was still being used by any of the branches. The M4 carbine is the superior weapon.

---

The M4 is still based on the M16 though. It's basically a carbine version of the platform as I understand it.

---

Smaller version, more reliable, easy to use, better in urban warfare situations.

Going to the range with "training rounds" sounds like a not so fun day of FTEs and SPORTS. No thank you. Give me the good stuff and let's go to work.

BurnetAggie99 said:

---

The real question is what do the Marines think of this rifle

---

Marines won't get it until we get the Army's beat up nasty seconds. We're typically a few years behind emerging technology

WestTexAg12 said:

---

BurnetAggie99 said:

---

The real question is what do the Marines think of this rifle

---

Marines won't get it until we get the Army's beat up nasty seconds. We're typically a few years behind emerging technology

---

We Leathernecks can show them how to shoot it

Thanks Gunny. I have watched the NGSW program for the past three years and I don't understand the Army's methodology. Seven years ago, the Army unilaterally adopted the M855A1 cartridge because it achieved ~200fps faster muzzle velocity and the tungsten bullet was "greener" than the lead core M855 and M193. That's all good but when testing the M855A1 in the M4 and M27, the Marine Corps observed a 30% reduction in barrel life because the higher chamber pressure and heat caused significant barrel erosion and degradation in the neck of the chamber. Maybe it's justified but every advantage comes with a tradeoff in reliability, maintainability, availability, and cost

The NGSW program (under PEO Soldier Lethality) relentlessly pursued two key performance parameters, range and terminal ballistics, and has been seemingly oblivious to all of the other system attributes that were traded away to obtain the range and terminal ballisticperformance.

Two of the foundational assumptions for NGSW seem to be that:

1. Service rifles and machine guns will need longer range because Soldiers will be fighting (somewhere) that will allow Army infantry to engage the enemy at distances of 500-1000m, which is distinctly unlike most infantry combat since the invention of gunpowder.

2. Our enemies will be equipped with plate body armor that is as good or better than US body armor and will require far more energy to penetrate the armor than the 5.56mm NATO.

OK. I will press the " I believe " button and accept the assumptions. Even so, the things that are traded away to get range and improved terminal ballistics are very significant and costly.

1. It reduces number of rounds carried per soldier

2. The weight of the XM7 compared to the M4 is heavier as is the ammo.

3. The cost of the XM7 is ~3x the cost of an M4 and the cost of the FCS is at least 2x the price of a Trijicon ACOG.

4. The cost of the ammo is anyone's guess because it is a brand new production line with NO civilian customers because it will be a cartridge only for military use.

5. The elephant in the room is chamber pressure. For all the shortcomings of the 5.55mm NATO cartridge, it really is at a sweet spot when it comes to balancing performance with durability and service life. The 5.56x45mm NATO has a chamber pressure of 58,000 rounds. Metallurgy to provide a 7000-10000 round barrel life is affordable. However, as chamber pressure increases, barrel erosion also increases geometrically. It's not only greater PSI but more square inches of surface are in the chamber and barrel. For comparison, a .50 BMG has a lot more surface area in the chamber and barrel than a 5.56mm but it has a slightly lower chamber pressure of 55,000psi. The Army will not reveal what the chamber pressure is for the Sig 6.8mm cartridge but a good guess would be around 65,000psi. That might reduce the accurate life of a barrel to ~3000-5000 rounds and the life of the bolt would also drop significantly. A 3000 round service life in combat might be mere weeks. How much will all of those replacement barrels cost? Nobody knows (except Sig). It's probably a fair guess that a large portion of the cost for the XM7 is due to the metallurgy and proprietary heat treatment that Sig must use to manufacture those receivers.

6. The Sig design proposal includes an option to retrofit the NGSW machine gun for a 7.62x51mm barrel and chamber for more economical and lower cost ammo and would allow for training on existingsnall arms ranges with a 3600m SDZ. The Army opted not to buy the 7.62mm receivers and instead to buy a ballistically similar (but not identical) 6.8mm reduced charge training munition (RTCM). When switching from RTCM to combat ammo, the weapons will have to be zeroed again.

The 6.8mm Sig has amazing performance. It has a very flat trajectory and is still at supersonic velocity 1000m from the muzzle. It will almost certainly be lethal to any human regardless of body armor to well over 600m and will penetrate thin skinned vehicles. Axknowledging all of that, can the price to procure and sustain it be justified? If it is so unquestionably cost effective relative to 5.56mm platforms, why is the Army planning to field it only to infantry and USASOC?

WestTexAg12 said:

---

BurnetAggie99 said:

---

The real question is what do the Marines think of this rifle

---

Marines won't get it until we get the Army's beat up nasty seconds. We're typically a few years behind emerging technology

---

I wonder if the Corps has the money or interest since it only completed fielding of the M27 a few years ago?

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

---

I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

japantiger said:

---

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

---

I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

---

"SIG Sauer developed an innovative thinner, lighter hybrid brass/alloy cartridge to pair with 6.8-millimeter projectiles, reducing overall weight by 30 percent. The new combination yields rounds that weigh about the same as the 5.56mm ammunition the M4/M249 fire. But it packs a much heavier punch, able to lethally pierce body armor close-in and at longer ranges."

NGSW
OPTIC

74OA said:

---

japantiger said:

---

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

---

I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

---

"SIG Sauer developed an innovative thinner, lighter hybrid brass/alloy cartridge to pair with 6.8-millimeter projectiles, reducing overall weight by 30 percent. The new combination yields rounds that weigh about the same as the 5.56mm ammunition the M4/M249 fire. But it packs a much heavier punch, able to lethally pierce body armor close-in and at longer ranges."

NGSW
OPTIC

---

I'm still a little confused...does this say the round is heavier, but the cartridge is lighter, so net-net, no change in weight vs M4/M16 ammo?

I guess it was the bullpup rifle design that resulted in overall less ammo weight...and that didn't make the cut.

You're reading what I'm reading. No idea what "weigh about the same" encompasses.

As the article mentions, Army is continuing to press SIG to lower the overall weight of the weapon and the optic continues to impress.

BurnetAggie99 said:

---

The real question is what do the Marines think of this rifle

---

As long as the rifle comes with crayons, Marines will be fine.

japantiger said:

---

74OA said:

---

japantiger said:

---

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

---

I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

---

"SIG Sauer developed an innovative thinner, lighter hybrid brass/alloy cartridge to pair with 6.8-millimeter projectiles, reducing overall weight by 30 percent. The new combination yields rounds that weigh about the same as the 5.56mm ammunition the M4/M249 fire. But it packs a much heavier punch, able to lethally pierce body armor close-in and at longer ranges."

NGSW
OPTIC

---

I'm still a little confused...does this say the round is heavier, but the cartridge is lighter, so net-net, no change in weight vs M4/M16 ammo?

I guess it was the bullpup rifle design that resulted in overall less ammo weight...and that didn't make the cut.

---

japantiger said:

---

74OA said:

---

japantiger said:

---

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

---

I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

---

"SIG Sauer developed an innovative thinner, lighter hybrid brass/alloy cartridge to pair with 6.8-millimeter projectiles, reducing overall weight by 30 percent. The new combination yields rounds that weigh about the same as the 5.56mm ammunition the M4/M249 fire. But it packs a much heavier punch, able to lethally pierce body armor close-in and at longer ranges."

NGSW
OPTIC

---

I'm still a little confused...does this say the round is heavier, but the cartridge is lighter, so net-net, no change in weight vs M4/M16 ammo?

I guess it was the bullpup rifle design that resulted in overall less ammo weight...and that didn't make the cut.

---

The new cartridge is 6.8x51mm so it is as long as the 7.62mm NATO cartridge. The receiver is the size of an AR10 rather than an M4/AR15.

The hybrid case is a combination of stainless steel and brass, not polymer and brass. General Dynamics proposed a rifle that used a composite polymer case but Sign won out. Regardless of the weight difference, the XM7 is being fielded with 20 round magazines.

As I was searching for this information, I found this very informative summary that includes the actual chamber pressure. My guess was way low. It's actually 80,000 psi. That ultra high pressure is what necessitates the hybrid case with stainless steel. The cost is going to be far more than 5.56mm ammo. This article is from 2022 and refers to the rifle as the XM5 rather than the XM7. No idea what differentiates the two.


https://www.snipercountry.com/277-sig-fury-6-8x51mm/

Quote:

---

The XM5 is about 2 lbs heavier than the M4, ammo weighs almost 3 times as much meaning the average grunt is going to carry a lot less ammo, and we have yet to see the hyper need for this magically new cartridge like the Army claims there is.

---

A loaded 30 round aluminum magazine of 5.56 weighs 1.98 pounds. If the 6.8 ammo weight 3x what 5.5.56mm then each Soldier will be carrying 140 rounds of ammo that weighs 21 pounds vice 210 rounds of ammo that weighs 14 pounds.

Ulysses90 said:

---

japantiger said:

---

74OA said:

---

japantiger said:

---

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

---

I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

---

"SIG Sauer developed an innovative thinner, lighter hybrid brass/alloy cartridge to pair with 6.8-millimeter projectiles, reducing overall weight by 30 percent. The new combination yields rounds that weigh about the same as the 5.56mm ammunition the M4/M249 fire. But it packs a much heavier punch, able to lethally pierce body armor close-in and at longer ranges."

NGSW
OPTIC

---

I'm still a little confused...does this say the round is heavier, but the cartridge is lighter, so net-net, no change in weight vs M4/M16 ammo?

I guess it was the bullpup rifle design that resulted in overall less ammo weight...and that didn't make the cut.

---

japantiger said:

---

74OA said:

---

japantiger said:

---

Ulysses90 said:

---

The XM7 (Next Generation Squad Weapon) raises a lot of questions about how the requirement was derived and the combat modeling that supported the decision.

• Was there data to suggest that 5.56mm hits were not putting down the bad guys? The Marine Corps (and as far as I know the Army also) found no evidence of this over the past 20 year albeit they weren't shooting a enemy wearing plate body armor: "It's not the round, it's the shooter. If we hit them [enemy combatants], we put them down. The problem is we're not very good at hitting moving targets" (Johnson, 2007)." -Gen James Conway

• Historically ~90% of small arms engagements have taken place at distances of <300m. Is there evidence to suggest that this is going to change abruptly to require that every infantryman be equipped with a 6.8mm weapon that is lethal out to 1000m (assuming that the shooter can hit the target)?

• Since the basic ammo load if a rifleman drops from 210 rounds (seven 30 round magazines of 5.56mm) to 140 rounds (seven 20 round magazines of 6.8mm), how do you achieve a 50% improvement in accuracy to offset the 33% reduction in ammo?

• Does Army doctrine on the use of small arms fire for suppression change when ammunition quantities carried by soldiers are reduced by 33%?

• If the $10k NGSW Fire Control System (a.k.a. the optic) is going to provide the magic that allows a rifleman to increase accuracy (the ability to hit the target) by 50%, how much would it improve the performance of riflemen using the M4 Carbine?

After the decision to move to the 6.8mm cartridge, the Army has acknowledged that the surface danger zone is significantly greater than the 3600m for 5.56mm and 7.62mm NATO cartridges. They won't say exactly what the SDZ is for a 6.8mm cartridge but it is probably closer to the 7200m distance of the .50 BMG. This means that approximately 80% of the small arms ranges on Army installations cannot support training with the 6.8mm cartridge because their SDZs are too short.

Furthermore, the 6.8mm Sig will blow holes through standard AR500 plate steel targets at close to medium distances. It will also penetrate completely through the standard target protection berms for pop-up targets which means that the 6.8mm Sig will cause significant damage to existing range infrastructure if it is used in training.

Consequently, the Army has decided to field a reduced charge 6.8mm training cartridge with different ballistic characteristics from the 6.8mm cartridge that will be used in combat. What's not to like?

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I thought part of the change with the weapon; was the new ammo associated with it was polymer/composite case (and shorter case) that reduced weight by up to 40%...if so, why carry less ammo? I assume that is due to the increased ~2lbs on the weapon? I assume the new XM157 Fire Control optic, must provide a big accuracy boost...though I can't find numbers on that.

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"SIG Sauer developed an innovative thinner, lighter hybrid brass/alloy cartridge to pair with 6.8-millimeter projectiles, reducing overall weight by 30 percent. The new combination yields rounds that weigh about the same as the 5.56mm ammunition the M4/M249 fire. But it packs a much heavier punch, able to lethally pierce body armor close-in and at longer ranges."

NGSW
OPTIC

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I'm still a little confused...does this say the round is heavier, but the cartridge is lighter, so net-net, no change in weight vs M4/M16 ammo?

I guess it was the bullpup rifle design that resulted in overall less ammo weight...and that didn't make the cut.

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The new cartridge is 6.8x51mm so it is as long as the 7.62mm NATO cartridge. The receiver is the size of an AR10 rather than an M4/AR15.

The hybrid case is a combination of stainless steel and brass, not polymer and brass. General Dynamics proposed a rifle that used a composite polymer case but Sign won out. Regardless of the weight difference, the XM7 is being fielded with 20 round magazines.

As I was searching for this information, I found this very informative summary that includes the actual chamber pressure. My guess was way low. It's actually 80,000 psi. That ultra high pressure is what necessitates the hybrid case with stainless steel. The cost is going to be far more than 5.56mm ammo. This article is from 2022 and refers to the rifle as the XM5 rather than the XM7. No idea what differentiates the two.


https://www.snipercountry.com/277-sig-fury-6-8x51mm/

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The XM5 is about 2 lbs heavier than the M4, ammo weighs almost 3 times as much meaning the average grunt is going to carry a lot less ammo, and we have yet to see the hyper need for this magically new cartridge like the Army claims there is.

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A loaded 30 round aluminum magazine of 5.56 weighs 1.98 pounds. If the 6.8 ammo weight 3x what 5.5.56mm then each Soldier will be carrying 140 rounds of ammo that weighs 21 pounds vice 210 rounds of ammo that weighs 14 pounds.

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Confusing. The Sept 2023 article I linked above says the final 6.8 designed for the XM7 weighs about what the 5.56 weighs, not three times as much?

TexasRebel said:

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So

Surplus to the public?

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In the Middle East?

Did anyone else lose all their firearms in a bizarre boating accident?

IndividualFreedom said:

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Did anyone else lose all their firearms in a bizarre boating accident?

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Probably why my fish finder radar is going nuts. Probably.

This guy is finding your firearms.

BurnetAggie99 said:

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The real question is what do the Marines think of this rifle

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They'll have to find out when they pick a few up off the battlefield someday

Is that a .22LR?

Almost looks like a Marlin 60.

Naming convention was changed because Colt has a rifle that is designated as XM5 and this would have both caused confusion between the two but also some patent infringements. So the Sig was renamed to XM7.

Overall the platform looks to be kind of an AR-10 carbine version in 6.8. Much of the same ergos, better ballistics than either 5.56 or 7.62. I'm interested to see how the cartridge case holds up over time with the two piece stainless and brass casing - that seems to be something that would immediately be a red flag to me as a failure point.

Barrel life looks like it's going to be roughly the same as an M4, which means that even when the 7k-10k number is hit, the barrel still has plenty of life left and can still achieve more than sufficient battlefield accuracy.

Any change in primary infantry weapon is going to be met with a lot of pushback, support, arguments, politics and everything in between. Personally, I think going with the M4 platform but upgrading the 5.56 to something different cartridge wise would have been a better move, but the Army is going to do whatever they want no matter what.

I don't understand what the claim is based on that the barrel life of the XM7 is going to be about the same as the M4. The pressure, heat, and surface area are important factors in the erosion and fatigue life calculation for barrels. The relationship isn't linear between thes factors and barrel life decrease much faster at very high pressures.

You also see accuracy drop significantly as the number of rounds fired through the barrel accumulates over time in high chamber pressure sniper rifles. The .308 remained prevalent for decades in part because it maintained accuracy far longer than higher velocity/pressure cartridges.

The XM7 isn't going to be immune to these factors because there's no free ride. Machine gun barrels will suffer much faster wear because the temperatures will have an annealing effect on the barrel. Heating undoes heat treatment especially when cooling happens slowly without quenching.

Nothing is free indeed but if it drops 6 feet less than a 6.5 creedmor at 1000 yards etc. it really is pretty incredible, and the other thing is that the gun is really just half of the 'solution' to the army, the other being the computer brain optic.

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However, to maximize the capabilities of this rifle, the Next Gen ammunition it was designed for will be the key. From what I understand, the .277 Fury round from the standard issue 13-inch barrel is capable of 20-30 percent more energy on target at 1,000 yards than a 6.5 Creedmoor.

It also drops around 6 feet less than the 6.5 Creedmoor at 1,000 yards. That's incredible but I have not been able to test that myself.

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Everyone has an opinion on ammo in the hunting world, but it sounds like eventually the 277 fury is going to be more popular, down the road. 308 will still be much more common, even in a hundred years, imho.

FJB24 said:

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Everyone has an opinion on ammo in the hunting world, but it sounds like eventually the 277 fury is going to be more popular, down the road. 308 will still be much more common, even in a hundred years, imho.

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One of the reasons I bought a Springfield M1A Scout a few years back (and subsequently lost it in a tragic boating accident, Mr. ATF agent; go do something productive with your life). .308 and 7.62x51 are readily available and relatively inexpensive. Plus, it's a really fun platform if you don't feel the need to load it down with accessories that cost more than the rifle itself.