Alternative new rifle cartridges

MadRat said:
Interesting concept that was truly before its time. It doesn't appear to solve any storage problems with the tround concept. But it is interesting. It kind of reminds me of exotic ideas like cannister disc charges fed separate from the bullet supply. While interesting it doesn't really solve any problems without adding new ones
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The peak of silly small arms will always be the caseless bulk liquid monopropellant rifle, which I wish there was more info on.
 
SuperShark said:
You don't want a bottle of hydrazine in the buttstock of your rifle?!
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The first exploding hydrazine is probably the end of the program. But if you could synchronize barrel ports to continue building pressure increases then theoretically your original cartridge could shrink quite a bit. Probably looks like something out of Logan's Run at the end of the barrel flash.
 
MadRat said:
The first exploding hydrazine is probably the end of the program. But if you could synchronize barrel ports to continue building pressure increases then theoretically your original cartridge could shrink quite a bit. Probably looks like something out of Logan's Run at the end of the barrel flash.
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No, the things used in Logan's run were acetylene flames, and not pushing any projectiles.

Any gun doing a long burn down the barrel to increase velocity is likely going to have a blue-white plasma torch coming out the muzzle. Or plasma torches coming out the sides of the muzzle brake.

Also, you'd need to really carefully time the burn time. Any combustion happening outside the barrel is going to be LOUD. Witness what happens when some [expletives deleted] cuts a 7.62NATO barrel down to 12". Between the concussion and flames it's effectively a flashbang grenade going off about 20" in front of the shooter's face. Ow.

Ian McCollum suggested that the best use of a full auto 12" 7.62NATO would be to establish dominance at the Knob Creek (edit) night MG shoot.
 
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Acetylene burns awfully fast and hot. It also mixes with air extremely fast which is why you probably would not get much percussion if the timing was late. But put it into a balloon or bag, to keep air out, and a spark igniting the gas will create a spectacular thunderflash. Not much visible light but lots of boom.
 
Scott Kenny said:
That's a deliberate design choice. Gas tube goes pop on an AR, you're left with a straight pull bolt action rifle. The rifle still works, though the T-handle is in a lousy spot to work the bolt repeatedly. Bad ergonomics, you have to break your cheek weld after every shot.

But the rifle will still go bang! You can still fight back. Or at least fight your way to a fully working rifle.
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Or you could beef up the tube, adjust the port size on the gas block, go to a piston AR. . . lots of options.
 
Sferrin said:
Or you could beef up the tube, adjust the port size on the gas block, go to a piston AR. . . lots of options.
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Beef up the tube and then you get runaway guns because it's fired so many rounds the next round in the chamber cooks off. And or burn the handguards off so now you can't control the thing.

Pop the gas tube and it forces the shooting to slow down and keeps the gun working longer while still controlled.

Piston is an option, short stroke gas pistons is the typical setup for a belt-fed upper. Where you do want a lot more firing than for an individual rifle. Personally, I'm annoyed that most belt-fed uppers are on the order of 5k.
 
Scott Kenny said:
Beef up the tube and then you get runaway guns because it's fired so many rounds the next round in the chamber cooks off. And or burn the handguards off so now you can't control the thing.

Pop the gas tube and it forces the shooting to slow down and keeps the gun working longer while still controlled.

Piston is an option, short stroke gas pistons is the typical setup for a belt-fed upper. Where you do want a lot more firing than for an individual rifle. Personally, I'm annoyed that most belt-fed uppers are on the order of 5k.
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I'm not a fan of short stroke piston ARs, it puts an off axis /rotational force from the 12 o'clock on the bolt vs the Stoner system. To be clear I don't think it's always bad, just at that point why are you using an AR. If you asked me, why not make a short stroke extruded pipe gun like a SCAR/CZ BREN etc and have a pull tab on the belt instead of a cover.

Though... I don't know how it would work, but I love the aesthetic vibe of a belt fed TRW LMR.
 
Scott Kenny said:
Beef up the tube and then you get runaway guns because it's fired so many rounds the next round in the chamber cooks off.
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So adjust the port size on the barrel. You need X amount of gas to cycle the action. If pressure is higher then make the port smaller so the same amount of gas is tapped off. (Of course then you're underpowered when using standard ammunition. Good reason to use a piston or an adjustable gas block. Come to think of it they're already available.)

https://suparms.com/750-adjustable-gas-block-stainless-steel-solid-set-screw-melonite-finish.html
 
Sferrin said:
So adjust the port size on the barrel. You need X amount of gas to cycle the action. If pressure is higher then make the port smaller so the same amount of gas is tapped off.
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Or design the ammunition to have the correct pressure at the gas port in the first place.



Sferrin said:
(Of course then you're underpowered when using standard ammunition. Good reason to use a piston or an adjustable gas block. Come to think of it they're already available.)

https://suparms.com/750-adjustable-gas-block-stainless-steel-solid-set-screw-melonite-finish.html
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Yep. But the gas tube as the design weak point was a deliberate choice by Stoner et al to leave the rifleman with a working rifle when the automatic parts break.
 
People on Youtube keep bagging on use of 6.8 mm and 6.5 mm. One of the videos I saw yesterday demonstrated 6ARC. Another demonstrated 6MAX. The latter was much better volume in a clip which certainly is better than the 6.8 mm. Both videos had compelling arguments but also identified weaknesses with AR designs. The 6MAX resembles the 5.56 x 45 mm too much imho. Their arguments are perfectly valid but they need to address the elephant in the room regarding pressures and rounds carried.
 
Scott Kenny said:
Or design the ammunition to have the correct pressure at the gas port in the first place.
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No such thing as something for nothing. Reduced the pressure back to 62ksi and you may as well be shooting standard 855.
 
Sferrin said:
No such thing as something for nothing. Reduced the pressure back to 62ksi and you may as well be shooting standard 855.
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Not the maximum chamber pressure.

The pressure in the barrel when the bullet passes the gas port and lets whatever pressure is in the barrel into the gas system. For the fraction of a second that the bullet is holding pressure in the barrel after the gas port.

I don't have the interior ballistics calculators (or powder burn rate data) to know what that number is for the Stoner/AR gas system, but that gas system was built around a certain operating pressure. Jim Sullivan, the co-designer of the AR, is on record that the ball powder that was forced on the M16 was 10,000psi too high at the port even though it was acceptable at the chamber. This drove the cyclic rate from ~750rpm clear up to around 950, IIRC. Assuming a linear relationship between port pressure and cyclic rate, and if I'm doing my proportions correctly (this time), that gives us an intended port pressure of about 37,500psi. (That's at least in the right order of magnitude...)

Every gas operated rifle is designed around a specific port pressure, and regardless of the chamber pressure if your has dropped to 37,500psi or whatever the rifle was designed for at the port, the mechanical system will not care. Could be a 42kpsi round, could be 82kpsi.
 
Frangiible flechettes r possible so no "considered to be cruel" bodily effects therefore a 4.32mm diameter flechette carrying bullet might be the size for body armor & light vehicles. An augmenting 10mm rifle would still be needed to deliver bullets w micro shaped charges though.
 
Scott Kenny said:
No, the things used in Logan's run were acetylene flames, and not pushing any projectiles.

Any gun doing a long burn down the barrel to increase velocity is likely going to have a blue-white plasma torch coming out the muzzle. Or plasma torches coming out the sides of the muzzle brake.

Also, you'd need to really carefully time the burn time. Any combustion happening outside the barrel is going to be LOUD. Witness what happens when some [expletives deleted] cuts a 7.62NATO barrel down to 12". Between the concussion and flames it's effectively a flashbang grenade going off about 20" in front of the shooter's face. Ow.

Ian McCollum suggested that the best use of a full auto 12" 7.62NATO would be to establish dominance at the Knob Creek (edit) night MG shoot.
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Oooh. OOOH. Seen that, shot it :cool:

One of the guys at our club had a cut-down FAL with a huge muzzle brake. Ran a BREN magazine in it with 30 rounds. Used it for DSR competition.
Sounded like he was running around firing a howitser. Great fun, as long as you were not standing next to him :D
 
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Scott Kenny said:
Not the maximum chamber pressure.

The pressure in the barrel when the bullet passes the gas port and lets whatever pressure is in the barrel into the gas system. For the fraction of a second that the bullet is holding pressure in the barrel after the gas port.

I don't have the interior ballistics calculators (or powder burn rate data) to know what that number is for the Stoner/AR gas system, but that gas system was built around a certain operating pressure. Jim Sullivan, the co-designer of the AR, is on record that the ball powder that was forced on the M16 was 10,000psi too high at the port even though it was acceptable at the chamber. This drove the cyclic rate from ~750rpm clear up to around 950, IIRC. Assuming a linear relationship between port pressure and cyclic rate, and if I'm doing my proportions correctly (this time), that gives us an intended port pressure of about 37,500psi. (That's at least in the right order of magnitude...)

Every gas operated rifle is designed around a specific port pressure, and regardless of the chamber pressure if your has dropped to 37,500psi or whatever the rifle was designed for at the port, the mechanical system will not care. Could be a 42kpsi round, could be 82kpsi.
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So you have a 2-setting gas block. One for higher pressure, one for standard. The gas tube then doesn't know or care what you're shooting. (Unless you forgot to check your ammo/ gas block setting. Worst case, just make a stronger gas tube. There are lots of possible solutions.)
 
Sferrin said:
So you have a 2-setting gas block. One for higher pressure, one for standard. The gas tube then doesn't know or care what you're shooting. (Unless you forgot to check your ammo/ gas block setting. Worst case, just make a stronger gas tube. There are lots of possible solutions.)
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Which works but is something for Private Schuckatelli to fiddle with and leave in the wrong setting (see British FALs being put into "Gas OFF").

It's also at least one other part with a lot more machining to do. Lose it and you have a bolt action rifle.

The other version is a self-regulating gas plug, but IIRC the better way to do those is 4 additional parts plus machining.

Tradeoffs.

Engineering your super-high pressure ammo to be close to standard pressure at the gas port via powder chemistry and burn rate and not monkeying with the gas system design is generally preferred.

That said, for the SOCOM HICAR rifle, I wouldn't be surprised if someone pitched a variation of the Benelli MR1 (aka Beretta Rx4 Storm) 5.56 rifle. It uses a variation of the Benelli self-adjusting gas system from shotguns so it can handle working pressures that double between low and high. It's also legitimately pretty self-cleaning, too.
 
Scott Kenny said:
Engineering your super-high pressure ammo to be close to standard pressure at the gas port via powder chemistry and burn rate and not monkeying with the gas system design is generally preferred.
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Which would mean you'd have to do the bulk of your acceleration well before the port which would likely drive up chamber pressures even higher. It would also put a bigger limitation on barrel length.
 
Sferrin said:
Which would mean you'd have to do the bulk of your acceleration well before the port which would likely drive up chamber pressures even higher. It would also put a bigger limitation on barrel length.
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Sure.

But the 14.5" barrels are the length they are due to port pressure and dwell time, to improve reliability.
 
jsport said:
Frangiible flechettes r possible so no "considered to be cruel" bodily effects therefore a 4.32mm diameter flechette carrying bullet might be the size for body armor & light vehicles. An augmenting 10mm rifle would still be needed to deliver bullets w micro shaped charges though.
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The .510 Beck I used as an example was to demonstrate large bore bullets do not need high pressures. May not get much boom in either a 10 mm or .510 round. But it certainly can fit electronics to chase laser reflections. They can probably come up with quite a few exotic applications like smoke markers, flash bangs, etc. The bat belt of guns lol
 
Sferrin said:
Not if you have a muzzle device permanently attached.
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Granted. As much as I otherwise hate pinned&welded since it makes it impossible to remove the gas block non-destructively.

But hopefully that law will get declared unconstitutional soon. Then I can rebuild my XM177E2 properly with the 1 in 12" twist barrel it should have.
 
MadRat said:
The .510 Beck I used as an example was to demonstrate large bore bullets do not need high pressures. May not get much boom in either a 10 mm or .510 round. But it certainly can fit electronics to chase laser reflections. They can probably come up with quite a few exotic applications like smoke markers, flash bangs, etc. The bat belt of guns lol
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MadRat said:
The .510 Beck I used as an example was to demonstrate large bore bullets do not need high pressures. May not get much boom in either a 10 mm or .510 round. But it certainly can fit electronics to chase laser reflections. They can probably come up with quite a few exotic applications like smoke markers, flash bangs, etc. The bat belt of guns lol
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To start from the beginning, what would you say is the actual function of an infantry small arm?
 
A good combine wpn start would be a dual barreled firing a 4.32x??mm over a 10X??mm payload/eventually guided bullet. This combo would be a derivative of the proposed infantry 2000 proposed. The definitive dismount compontent would not be the combo rifle though, it would be the cold vertical launch top attack missile/ATGM carried on the backpack as the infantry 2000 proposal appeared to seek.

Dispersed dismounts must be empowered as they are fewer in the West. ..and of course each dismount need be protected by a pack of robodogs & at least one humanoid robo bodyguard.
 
All -

Howdy !

“ Synchronized gas ports “ - see Gerald Bull “ Project Babylon “.
IMHO:
To truly synchronize multiple gas ports for purposes of sequentially adding propellant gas pressure behind a projectile ( maybe + sabot ) advancing down a “ bore “; would require multiple fast-acting solenoid valves…. along w/ necessary “ tubing “ connected to the high pressure source… and some computerized control + circuitry.

Other:
- One high Mv blast from the past would be the “ Paris Gun “ of WW 1.
Their 8 inch caliber barrels were “ about 90ft long “, and featured a chamber some
“ 13ft long “. Those guns had an “ Expansion Ratio of about 7 “.
“ The powder charge was 305 pounds of nitrocellulose-powder, and the shell weighed
264 pounds; so the ratio of Powder Charge to Bullet Weight was about 1.20 .”
Records show Mv attained was a little past 5,000 feet per second, w/ a “ chamber pressure of 55,000 psi “.
Source: Homer Powley “ The Powley Papers “ Guns & Ammo 1974 Annual “.

Note: A rifle w/ a notional 28” long barrel chambered in “ .22-250 “ would give an
“ expansion ratio “ of 7. Source: as noted, above.


6,000fps:
Decades ago….
cartridge “ wildcatters “ Robert Hutton and Bob Forker necked-down the .284 Winchester case to .224” caliber, in response to military programs request for a
cartridge that could propel a bullet to 6,000 fps.

Bullets tried were thick jacketed .224” cal of 31 - 50gr weight, made by a Dr. Eichorn.
Reports were, they shot some 2” groups @ 300yd, using barrel twist rates of 1-14 and
1-24.

They were able to propel 15gr sintered iron bullets to 5,485 fps on a charge of 54gr
IMR ( Improved Military Rifle ) 4064 powder.

The 15gr bullet reached 6,585fps top speed, and produced some 2” groups 100yd;
propelled by a charge of 50gr IMR4227 powder.


With regards,
357Mag








With regards,
357Mag
 
MadRat said:
People on Youtube keep bagging on use of 6.8 mm and 6.5 mm. One of the videos I saw yesterday demonstrated 6ARC. Another demonstrated 6MAX. The latter was much better volume in a clip which certainly is better than the 6.8 mm. Both videos had compelling arguments but also identified weaknesses with AR designs. The 6MAX resembles the 5.56 x 45 mm too much imho. Their arguments are perfectly valid but they need to address the elephant in the room regarding pressures and rounds carried.
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80 ksi 5.56 is the way.
 
I'm not convinced these very high pressures are a good idea but if you are going through all the trouble to field weapons able to handle this abuse why restrict yourself to 5.56mm which isn't ideal for extended ranges?

The Army needs to stop thinking it can find some perfect one-size-fits-all solution. The NGSW craziness is still ongoing and yet SOCOM seems to have found a separate container of special Kool-Aid and now think "M855A1 worked well so we'll just crank that up to 11 and then we can engage tangos a kilometer away with our 5.56mm M4 carbines".
 
Colonial-Marine said:
I'm not convinced these very high pressures are a good idea but if you are going through all the trouble to field weapons able to handle this abuse why restrict yourself to 5.56mm which isn't ideal for extended ranges?
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You mean feature creep? $$$
 
357Mag said:
[...] cartridge that could propel a bullet to 6,000 fps.

Bullets tried were thick jacketed .224” cal of 31 - 50gr weight, made by a Dr. Eichorn.
Reports were, they shot some 2” groups @ 300yd, using barrel twist rates of 1-14 and
1-24.

They were able to propel 15gr sintered iron bullets to 5,485 fps on a charge of 54gr
IMR ( Improved Military Rifle ) 4064 powder.

The 15gr bullet reached 6,585fps top speed, and produced some 2” groups 100yd;
propelled by a charge of 50gr IMR4227 powder.
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Yowza that's spicy!

But barrel life with sintered iron(!) projectiles must have been terrible.



Colonial-Marine said:
I'm not convinced these very high pressures are a good idea but if you are going through all the trouble to field weapons able to handle this abuse why restrict yourself to 5.56mm which isn't ideal for extended ranges?
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Because SOCOM wants to leech off local ammunition stores when they run out of magic bullets.

Literally the only reason anyone is sticking with 5.56 in the US Army. Well, at least for Line Infantry. Otherwise, the Army is (finally) treating the 5.56 as a PDW round in the same sense as the old .30 Carbine. Actual 11-series MOS grunt infantry get the 6.8x51 rifles, everyone else gets a 5.56 rifle. 18-series Special Ops grunts get super-spicy 5.56 so they can use local friendly ammo supply in an emergency, and will likely use 7.62 Minimi or even Knights AMG in 7.62 or 6.5creed.
 
Colonial-Marine said:
I'm not convinced these very high pressures are a good idea but if you are going through all the trouble to field weapons able to handle this abuse why restrict yourself to 5.56mm which isn't ideal for extended ranges?
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80k is milspec proof. If you can afford a better bolt like KAC or LMT, which already surpasses that, then you can afford better ammunition to couple with it, but that pressure range is also the limit of brass as is.

HICAR would come directly into conflict with the MRGG lineups, which is pretty low tech and uses in inventory systems so I think it’s not going to result in anything substantial for SOCOM, but the data could feed elsewhere.
 
Colonial-Marine said:
I'm not convinced these very high pressures are a good idea but if you are going through all the trouble to field weapons able to handle this abuse why restrict yourself to 5.56mm which isn't ideal for extended ranges?

The Army needs to stop thinking it can find some perfect one-size-fits-all solution. The NGSW craziness is still ongoing and yet SOCOM seems to have found a separate container of special Kool-Aid and now think "M855A1 worked well so we'll just crank that up to 11 and then we can engage tangos a kilometer away with our 5.56mm M4 carbines".
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I've done some math and you're fine with rifle length gas systems, basically fine with mid length gas systems and a little over pressure for carbine using certain COTS powder/bullet combos for 80ksi. Also getting stupid MV and absurdly flat shooting, using Emeric Daniau's 5.56mm neckless case concept, NAS-3 type cases, and COTS modern long range bullets. I'm waiting to test it for the fall when I have more free time.
 
Scott Kenny said:
Literally the only reason anyone is sticking with 5.56 in the US Army. Well, at least for Line Infantry. Otherwise, the Army is (finally) treating the 5.56 as a PDW round in the same sense as the old .30 Carbine. Actual 11-series MOS grunt infantry get the 6.8x51 rifles, everyone else gets a 5.56 rifle. 18-series Special Ops grunts get super-spicy 5.56 so they can use local friendly ammo supply in an emergency, and will likely use 7.62 Minimi or even Knights AMG in 7.62 or 6.5creed.
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6.8x51 is brain damaged but I digress. I've been over that previously in this thread.
 
whatismoo said:
6.8x51 is brain damaged but I digress. I've been over that previously in this thread.
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Take a .308 case necked down to 5.56 with a 90 gr bullet. :D (Or there are some 89gr tungsten powder sintered that are the same size as a 69gr Match King apparently.)
 
Sferrin said:
Not a 50 BMG. More like a 50 AE or 500 S&W. (Or better yet, a 12ga.)
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.510 Beck was the suggestion, or .510 Grizzly as my suggestion.
I still think that if the consensus is that 6.8x51mm and it's rifle are too heavy, a vest full of ~700 grain bullets and a ShAmeriKan-12 may not raise moral as much as desired.
 

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