Alternative new rifle cartridges

CastleBravo

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IMO the cost argument falls apart when you have to buy new receivers. NAS3 cases have more internal volume so it's possible a longer bullet could fit to get better ballistics in a 62 grain projectile. Personally I think that the steel case should be a fairly large warning that it'll blow up guns. There's also the prospect of mixing NAS3 with the neckless geometries of 5.56 that TV and some people online have played with to get the longer bullet in the same OAL. I've heard some scuttlebutt that steel has odd neck tension issues that might preclude this, but the general point is that 5.56x45's formfactor is absolutely not pushed to the limit, and there's room for a rebarrel/bolt upgrade that should make 5.56 shoot absurdly flat and punch through velocity limited plates (which is most ceramics and steel) at reasonable ranges.

A while back I sketched out a concept for 3300 ft/s 62gr with the G7 of 7N6 (.168) which ended up being comically flat shooting (a 300-350m battle zero ends up mathing out to fairly point and shoot to 500m.

View attachment 811207 View attachment 811206

Weird case geometry could work but you would lose the ability to fire standard 5.56 ball ammo for training, and the ammo cost is likely far higher than new receivers/mags in the long term. Going to something like a 75gr VLD would give a G7 over .2, and it could be done with existing cases, bullets, barrels, and bolts. It would just need a slightly longer receiver set and magazine.
 
If yall are going to mess with chamber dimensions, the phrase that pays is "Ackley Improved"

blown out front of the case, sharper case shoulder. It can basically put 150gr .30cal bullets at .300WM speeds out of a .30-06 case.
 
Agree w whatismoo that depending on too few rounds is hazardous. Clouds of uas & swarms of ugvs better relieve the infantry of every task but sharpshooting.

BTW: a carbine is never going to do a rifle"s job no matter what some RFP says. If you're close enough for high volume carbine work the jazzed up 556rds allows u to carry enough ammo, these 6xxs do not.

It appears current continuous building clearing might call for return of high volumes of flechettes. A compound w 1 house+ basement & 1 garage, 2 sheds, 3 underground shelters uses up all your rds & grenades just so you get shot in the back.
It must not be a wound/maiming rd/wpn.though.
 
If yall are going to mess with chamber dimensions, the phrase that pays is "Ackley Improved"

blown out front of the case, sharper case shoulder. It can basically put 150gr .30cal bullets at .300WM speeds out of a .30-06 case.
Also, the Ackley Improved geometry allows you to still use the original ammunition safely.

A .30-06 Ackley Improved normally chambers and fires standard .30-06 at a slight loss in power as the brass case expands to fill the larger chamber.

Hunters shooting Ackley calibers routinely do this to fire-form new brass to reload.
 
If the new 6.8mm weapons are that problematic, is Textron's 6.8CT alternative worth taking another look at? Supposed to be lighter than 7.62 alternatives. Is it likely to have less recoil and wear than the Sig Sauer? Could even look at using a 5.56CT as the carbine.
 
Weird case geometry could work but you would lose the ability to fire standard 5.56 ball ammo for training, and the ammo cost is likely far higher than new receivers/mags in the long term. Going to something like a 75gr VLD would give a G7 over .2, and it could be done with existing cases, bullets, barrels, and bolts. It would just need a slightly longer receiver set and magazine.
Neckless 5.56 is backwards compatible! 5.56 headspaces on the shoulder!
 
Weird case geometry could work but you would lose the ability to fire standard 5.56 ball ammo for training, and the ammo cost is likely far higher than new receivers/mags in the long term. Going to something like a 75gr VLD would give a G7 over .2, and it could be done with existing cases, bullets, barrels, and bolts. It would just need a slightly longer receiver set and magazine.
Longer receivers are NOT cheap. Even with recycling just about everything off existing weapons.

They're also heavier. IIRC the difference between the AR15 length and AR10 length receivers is half a pound (call it 0.2kg).
 
Longer receivers are NOT cheap. Even with recycling just about everything off existing weapons.

They're also heavier. IIRC the difference between the AR15 length and AR10 length receivers is half a pound (call it 0.2kg).

For low volume production just use billet receivers that can be easily stretched with a new CNC program and slightly longer aluminum blanks. That adds maybe $1-200 to the cost of each weapon vs forged sets (PSA has their Sabre billet sets for $270). LR308 pattern rifles are bigger in several dimensions, and the bolt carrier in particular is a lot heavier. A better comparison would be the Ruger SFAR which is basically a stretched AR15 that fires 308. AR-style rifles are probably the one thing American industry can make cheaper than the rest of the world.
 
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Agree w whatismoo that depending on too few rounds is hazardous. Clouds of uas & swarms of ugvs better relieve the infantry of every task but sharpshooting.

BTW: a carbine is never going to do a rifle"s job no matter what some RFP says. If you're close enough for high volume carbine work the jazzed up 556rds allows u to carry enough ammo, these 6xxs do not.

It appears current continuous building clearing might call for return of high volumes of flechettes. A compound w 1 house+ basement & 1 garage, 2 sheds, 3 underground shelters uses up all your rds & grenades just so you get shot in the back.
It must not be a wound/maiming rd/wpn.though.
Flechettes have awful soft tissue lethality and performed terribly in ACR! The only real improvement on 5.56mm at combat ranges (0-200m) was duplex 5.56mm.
 
Also, the Ackley Improved geometry allows you to still use the original ammunition safely.

A .30-06 Ackley Improved normally chambers and fires standard .30-06 at a slight loss in power as the brass case expands to fill the larger chamber.

Hunters shooting Ackley calibers routinely do this to fire-form new brass to reload.
I was thinking of Emerich Daniau's neckless 5.56 which doesn't actually change the chamber they just allow a longer bullet by cutting the neck off. 5.56x45mm headspaces on the shoulder so its basically free real estate to get better ogive length.

https://forums.delphiforums.com/autogun/messages/7908/89
 

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If the new 6.8mm weapons are that problematic, is Textron's 6.8CT alternative worth taking another look at? Supposed to be lighter than 7.62 alternatives. Is it likely to have less recoil and wear than the Sig Sauer? Could even look at using a 5.56CT as the carbine.
There's no reason, IMO, to go beyond improvements to 5.56. 6.8 as a concept is a dead end, but that doesn't sell guns people don't want to hear it.

Make 5.56 lighter and flatter shooting and put the rest of the money into some kind of atlatl for hand grenades. Maybe a lacrosse stick or one of the dog tennis ball throwers but stronger.
 
Flechettes have awful soft tissue lethality and performed terribly in ACR! The only real improvement on 5.56mm at combat ranges (0-200m) was duplex 5.56mm.
A whole new accurate cluster of three in a classless rd. These rds would need ballistic performance as short range lethal salvos so as do more than maim. Many rd mags would need to fit in a small wpn. Soldiers would need to carry hundreds.of rds. Ballistic development et al never lasted long enough to perfect these bullets. It was to difficult at the time & there were many issues which would have taken time.

The reason it would need to be near pistol size is that it would be a suppression wpn not a main battle rifle. E Stoner exclaimed most rifleman"s fire in Vietnam was preemptive suppressive fire and that is clearly seen on the current front as well. Once in genuine fire fight return back MBR.
 
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I was thinking of Emerich Daniau's neckless 5.56 which doesn't actually change the chamber they just allow a longer bullet by cutting the neck off. 5.56x45mm headspaces on the shoulder so its basically free real estate to get better ogive length.

https://forums.delphiforums.com/autogun/messages/7908/89
Oh, that's really interesting! That short neck makes me really nervous for bullet retention, though. It is violent inside a receiver under semi-auto conditions, nevermind full auto.



There's no reason, IMO, to go beyond improvements to 5.56. 6.8 as a concept is a dead end, but that doesn't sell guns people don't want to hear it.
6.8 is still viable as the MG/DMR round. It's just not viable as the basic Individual Weapon round.


some kind of atlatl for hand grenades. Maybe a lacrosse stick or one of the dog tennis ball throwers but stronger.
You do know that an M67 "baseball" grenade fits into those, right?
 
Make 5.56 lighter and flatter shooting and put the rest of the money into some kind of atlatl for hand grenades. Maybe a lacrosse stick or one of the dog tennis ball throwers but stronger.
It would've bern cool if someone invents something like, I don't know, a way to fire a grenade from a rifle.

Probably not realistic, but a boy can dream.
 
A whole new accurate cluster of three in a classless rd. These rds would need ballistic performance as short range lethal salvos so as do more than maim. Many rd mags would need to fit in a small wpn. Soldiers would need to carry hundreds.of rds. Ballistic development et al never lasted long enough to perfect these bullets. It was to difficult at the time & there were many issues which would have taken time.

The reason it would need to be near pistol size is that it would be a suppression wpn not a main battle rifle. E Stoner exclaimed most rifleman"s fire in Vietnam was preemptive suppressive fire and that is clearly seen on the current front as well. Once in genuine fire fight return back MBR.
A flechett pistol might also be used as personal counter UAS as well as counter mini-mine. Masses of Russian 3d printed mini-mines seem to be thing currently.
 
There's no reason, IMO, to go beyond improvements to 5.56. 6.8 as a concept is a dead end, but that doesn't sell guns people don't want to hear it.

Make 5.56 lighter and flatter shooting and put the rest of the money into some kind of atlatl for hand grenades. Maybe a lacrosse stick or one of the dog tennis ball throwers but stronger.
Textron also promoted a 5.56 and 6.5 version... i just like the CT concept.
 
How about an over-under .510 caliber semiauto using laser guided roundd and lighter but full auto .177 caliber at 4500+ fps? Attachment rails to add laser and computerized trigger. Point where it says and it decides good enough angle to shoot.
 
A whole new accurate cluster of three in a classless rd. These rds would need ballistic performance as short range lethal salvos so as do more than maim. Many rd mags would need to fit in a small wpn. Soldiers would need to carry hundreds.of rds. Ballistic development et al never lasted long enough to perfect these bullets. It was to difficult at the time & there were many issues which would have taken time.

The reason it would need to be near pistol size is that it would be a suppression wpn not a main battle rifle. E Stoner exclaimed most rifleman"s fire in Vietnam was preemptive suppressive fire and that is clearly seen on the current front as well. Once in genuine fire fight return back MBR.
Infantry flechettes were worked on fairly consistently by AAI from the 50s to 80s! They never could get them to reliably perform better than 5.56x45mm. It's a fairly clear dead end, even moreso with modern understanding of wounding mechanics.
 
Oh, that's really interesting! That short neck makes me really nervous for bullet retention, though. It is violent inside a receiver under semi-auto conditions, nevermind full auto.




6.8 is still viable as the MG/DMR round. It's just not viable as the basic Individual Weapon round.



You do know that an M67 "baseball" grenade fits into those, right?
For sure. In principle it should crimp fine, but who knows. Apparently the NAS3 cases crimp really well due to steel's mechanical properties vs brass but nobody has tried neckless NAS3 yet. It may run into weird tension issues.

In principle 6.8x51/ .277 Sig Fury should be a solid 7.62x51 replacement but I've heard it repeats some of the issues that .276 Pederson / 7x51mm had vs .30-06 (remember that 7.62x51 is a .30-06 service load analog)

I'm very aware they fit the tennis ball throwers, but you'd need to bulk it up for the mass AIUI. But yes I think they're a great idea.
 
It would've bern cool if someone invents something like, I don't know, a way to fire a grenade from a rifle.

Probably not realistic, but a boy can dream.
40mm grenade launchers and rifle grenades are cool! Someone should convince the army to adopt a fuse that doesn't take up like half the volume of the projectile!
 
A flechett pistol might also be used as personal counter UAS as well as counter mini-mine. Masses of Russian 3d printed mini-mines seem to be thing currently.
Flechettes and buckshot all have dispersion, range, and energy retention issues, and switching mags or carrying a shotgun kind of sucks.

The Russians have experimented with duplex 7.62x54r (though the second bullet looks bizzare). Duplex ammo would seem a promising approach the problem at least in close combat (0-200/300m) if ACR results are anything to go by, though it did blow up a gun, so there's development that needs to be done.
 

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I thought flechettes could be pretty devastating on impact under the right conditions. The bigger issue I read about was that they deflected rather easily off vegetation and other things, plus wind wasn't kind to them.
 
How about an over-under .510 caliber semiauto using laser guided roundd and lighter but full auto .177 caliber at 4500+ fps? Attachment rails to add laser and computerized trigger. Point where it says and it decides good enough angle to shoot.
Why not split the difference with a light (±60-65gr) ±5.5mm round at ±3150-3500... then you don't need two guns glued together or a laser telling the enemy where you are? Or expensive computers and a trigger that can break.
 
I thought flechettes could be pretty devastating on impact under the right conditions. The bigger issue I read about was that they deflected rather easily off vegetation and other things, plus wind wasn't kind to them.
They don't have the mass to actually fragment and cause damage like EPR type bullets do. IIRC they tend to ice pick through, or tumble but they're smaller than a normal bullet.

Wind and veg are definitely an issue until you go from flechettes to actual APFSDS with decent mass in the 1500m/s (5000 ft/s) range
 
Why not split the difference with a light (±60-65gr) ±5.5mm round at ±3150-3500... then you don't need two guns glued together or a laser telling the enemy where you are? Or expensive computers and a trigger that can break.
The big bullet muzzle energy would be around 12k ft-lbs, major stopping power for soft skinned vehicles and heavy body armor. With a computerized scope you can get armor piercing rounds into tight spots to kill vehicles. The lighter round would be to penetrate these new exotic body armors at close quarters. A computer would get rounds on target which is its own dimensional quality.
 
The big bullet muzzle energy would be around 12k ft-lbs, major stopping power for soft skinned vehicles and heavy body armor. With a computerized scope you can get armor piercing rounds into tight spots to kill vehicles. The lighter round would be to penetrate these new exotic body armors at close quarters. A computer would get rounds on target which is its own dimensional quality.

I'd rather have them carry more HE than a big bore gun. Rifles/carbines and their ammo should be getting lighter so they can carry more drones and explosives. I want something like the 40mm Pike round (2km semi-active laser missile fired from 40mm launcher) but with a multimode seeker including a scene matching mode so you can launch it fire and forget, or even use imagery from a drone or other sensor for indirect fire. That plus some drones would pair very well with smart helmets like the one Anduril is building.
 
The big bullet muzzle energy would be around 12k ft-lbs, major stopping power for soft skinned vehicles and heavy body armor. With a computerized scope you can get armor piercing rounds into tight spots to kill vehicles. The lighter round would be to penetrate these new exotic body armors at close quarters. A computer would get rounds on target which is its own dimensional quality.
Just use a light AT weapon instead of putting essentially a .50 BMG rifle on your assault rifle. The M72 LAW exists, you don't need a boys rifle for everyone.
 
Infantry flechettes were worked on fairly consistently by AAI from the 50s to 80s! They never could get them to reliably perform better than 5.56x45mm. It's a fairly clear dead end, even moreso with modern understanding of wounding mechanics. Ur
AAIs flechette shotgun rd reduced to caseless w /3, 4 or 6 projectiles doesn't need range above 50m. Flechette were a dead end because ur not gonna get 300m accuracy out of a dart. Probably barely a 100ms. That is not what a 50m rg "clear the close threat in the hide space" capability is after.
 
I'd rather have them carry more HE than a big bore gun. Rifles/carbines and their ammo should be getting lighter so they can carry more drones and explosives. I want something like the 40mm Pike round (2km semi-active laser missile fired from 40mm launcher) but with a multimode seeker including a scene matching mode so you can launch it fire and forget, or even use imagery from a drone or other sensor for indirect fire. That plus some drones would pair very well with smart helmets like the one Anduril is building.
I'm dubious of smart helmets, and that's all going to cost a ton of money but a beam riding or SALH rocket derived from APKWS should be eminently possible? Or just normal FPVs.
 
Just use a light AT weapon instead of putting essentially a .50 BMG rifle on your assault rifle. The M72 LAW exists, you don't need a boys rifle for everyone.
Thought we were discussing carrying to few rds. BMG & AT are low density assets especially when clearing rural compounds w 3 builds & 3 separately spaced cellular like ukr. Ur outta grenades & rds at the 2nd compound.
 
I'd rather have them carry more HE than a big bore gun. Rifles/carbines and their ammo should be getting lighter so they can carry more drones and explosives. I want something like the 40mm Pike round (2km semi-active laser missile fired from 40mm launcher) but with a multimode seeker including a scene matching mode so you can launch it fire and forget, or even use imagery from a drone or other sensor for indirect fire. That plus some drones would pair very well with smart helmets like the one Anduril is building.
Where is all that cash & carrying size & weight coming from? Whole Batts are asked to equip everyone to clear dwellings.
 
AAIs flechette shotgun rd reduced to caseless w /3, 4 or 6 projectiles doesn't need range above 50m. Flechette were a dead end because ur not gonna get 300m accuracy out of a dart. Probably barely a 100ms. That is not what a 50m rg 'clear the threat in the hide space" capability is after.
Why would you use flechettes instead of normal bullets and hand grenades? It's a lot of money for lower performance!

https://municion.org/wp-content/uploads/2022/11/06-047-BGC-011-1.pdf

Both AAI and Steyer flechette guns performed at best equal to and generally worse than an unmodified M16A2 with iron sights in the ACR 0-75m trials. In the 75-300m range band both flechette rifles performed uniformly worse than an unmodified M16A2 firing semi-automatic.

As the conclusions note, the flechettes performed worse than M855. The McDonnell Douglass Helicopter Corporation (i.e. Hughes) produced a multi-flechette ACR prototype but it was not mature enough for the firing trials, and MDHC was never able to solve the dispersion issue which have plagued every multi-flechette gun.
 

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Flechettes, as implemented in shotgun ammunition or SPEW programm do have issues, mainly due to simplification and cost cutting. More sophisticaded and expensive discarding APDS rounds can and did work.

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The graph shows [calculated] changes in the probability of hitting a target with bursts of fire when firing a PKM (from a tripod, with a mechanical sight) with the standard 7.62mm rifle cartridge and 10/2.5mm three-bullet cartridges (V0 = 1200 m/s) at different target dispersion values 100 m. The "Limit for 7.62" [black line in the middle] graph line is the ideal case, taking into account only the dispersion parameters and the median aiming errors, with all other shooting errors assumed to be zero. The lower curve corresponds to the calculated values, taking into account all shooting errors [for stanard 7.62x54r ammunition].
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7.62x54r, 10/4.5mm, 6x54mm(1981,) unified10/3.5mm, unified 10/2.5mm triple shot, 7.62x39, 5.45x39mm(7N6)

https://www.kalashnikov.ru/strelovidnye-puli-2/
 

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Why would you use flechettes instead of normal bullets and hand grenades? It's a lot of money for lower performance!
Guess have to repeat E Stoner said studies showed most fired rds in Vietnam were as recon fire not even at a target but at space someone could b hiding in. Video footage from the current front displays this repeatedly. As u stated 6xs are heavy & you won't have enough. To augment the MBR a pistol firing voumns of projectikes saves all ur grenade & rds for long shots & genuine grenade needs. Jeeper. how often must repeat.
 
Flechettes, as implemented in shotgun ammunition or SPEW programm do have issues, mainly due to simplification and cost cutting. More sophisticaded and expensive discarding APDS rounds can and did work.

Attchment 1:

Attachment 2, left to right:
7.62x54r, 10/4.5mm, 6x54mm(1981,) unified10/3.5mm, unified 10/2.5mm triple shot, 7.62x39, 5.45x39mm(7N6)

https://www.kalashnikov.ru/strelovidnye-puli-2/
Armored piercing flechetts r a different granimal.
 
Thought we were discussing carrying to few rds. BMG & AT are low density assets especially when clearing rural compounds w 3 builds & 3 separately spaced cellular like ukr. Ur outta grenades & rds at the 2nd compound.
Per RUSI, the typical loadout for a Ukranian assaulter is 12-15x 30 round magazines and 4-6x hand grenades, with resupply by UAV, in a seven soldier section. The shortage of ammunition I've referenced is in reference to the US Army moving to 6.8x51mm.
 
Per RUSI, the typical loadout for a Ukranian assaulter is 12-15x 30 round magazines and 4-6x hand grenades, with resupply by UAV, in a seven soldier section. The shortage of ammunition I've referenced is in reference to the US Army moving to 6.8x51mm.
Pretty much the same amount soldier were lugging during the Vietnam war.
And like back then it's about suppressive fire within the trench fight, too.
There's no single caliber fits all. Duplex and triplex are nice for increasing hit chances up to a certain distance but not really good for suppression. Suppression relies on heard shots as much as actual bullets landing nearby.
 
Guess have to repeat E Stoner said studies showed most fired rds in Vietnam were as recon fire not even at a target but at space someone could b hiding in. Video footage from the current front displays this repeatedly. As u stated 6xs are heavy & you won't have enough. To augment the MBR a pistol firing voumns of projectikes saves all ur grenade & rds for long shots & genuine grenade needs. Jeeper. how often must repeat.
You do not type very clearly. My point has always been that 6.8 is a mistake and 5.56 does the job relatively fine and has room to be further developed for higher performance at relatively low cost. The goal, in my view, is to lighten the rifle and ammunition if possible (through new alloys or moving away from brass cases) to allow the soldier to carry more ammunition.

I'm not sure how Stoner's allegation is terribly relevant when my argument has always been that more ammunition is better, and the path to this is mildly improved 5.56.
 
Per RUSI, the typical loadout for a Ukranian assaulter is 12-15x 30 round magazines and 4-6x hand grenades, with resupply by UAV, in a seven soldier section. The shortage of ammunition I've referenced is in reference to the US Army moving to 6.8x51mm.
If ur MBR is that large clearing close potentially threating hide spaces like inside a basement window requires not ur MBR rds. A Flechett pistol/carbine suppresses or incapacitates anyone in there though you don't have los on tgt.
 
Pretty much the same amount soldier were lugging during the Vietnam war.
And like back then it's about suppressive fire within the trench fight, too.
There's no single caliber fits all. Duplex and triplex are nice for increasing hit chances up to a certain distance but not really good for suppression. Suppression relies on heard shots as much as actual bullets landing nearby.
Yep, and in Vietnam we found that 5.56x45 was a great round!
 
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