M109A6 test bed for XM907 ERCA

Lets be honest. Its mutch cheaper to Take the L/52 maybe L/52A1 If ITS possible, some KAWEST Things (Semi Automatic loader) oe the old L/52 Autoloader in the Last offer and call it a day until the Autoloader is ready.
 
MadRat said:
Seems like you would want to start investing in a bit of stealth/survivability to these gold plated artillery solutions. Since you wouldn't want to stand out after firing off a barrage, what could be done?
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You GTFO from that firing position!

Fire one volley and leave.

Otherwise, you add the standard APS and a small DEW to pop drones.


jsport said:
dead tracks dead tracks dead tracks yeah, extremis maneuver (ie counter counterbattery) will require a new vehicle.

Live tracks refer to a vehicle equipped with return wheels, the rollers that support the upeer run of the track, like the M60, Abrams, Leopards, etc. Dead, or slack tracks, refer to AFVs that do not have this feature, wherein the track rests on top of the road wheels or sags under it's own tension.
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I don't believe that definition is correct. Live tracks have rubber bushings so that they tend to curl up, according to the Chieftain.
 
Kat Tsun said:
Because it's a relatively (to other artillery pieces) high pressure rifled gun. The point was to be backwards compatible with older 155mm, which is why it's 155mm, and not something useful like a 203mm smoothbore. Or even a 155mm smoothbore.
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Yes.


Kat Tsun said:
Copper driving bands are doable up to about 1,000 meters per second of muzzle velocity, at which point they become useless, because they are destroyed on firing.

Nickel driving bands survive but devour throat life.
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Don't the L7/M68 105mm tank guns use copper driving bands? The HEAT rounds do 1200m/s.


Kat Tsun said:
A smoothbore would solve both problems but that would require ERCA to be a completely different gun I guess.
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Had an odd thought: Two section barrel, breech end is rifled and muzzle end is not. If your propellant burn is slow enough, that might let you keep using copper driving bands because the shell isn't doing more than 1000m/s until the smoothbore section.
 
Scott Kenny said:
Had an odd thought: Two section barrel, breech end is rifled and muzzle end is not. If your propellant burn is slow enough, that might let you keep using copper driving bands because the shell isn't doing more than 1000m/s until the smoothbore section.
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That called Probert Rufling after the BRIT Colonel Probert who used it on the post WW2 super AA guns they fucked around with. Do believe one of the 4.5 inch guns had that set up. Which allowed the gun to smack things up to 50,000 feet.
 
Scott Kenny said:
I don't believe that definition is correct. Live tracks have rubber bushings so that they tend to curl up, according to the Chieftain.
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A dead track is more likely to be thrown, so not sure what is being argued here.
 
Scott Kenny said:
Yes.
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It's a bit irrelevant. Even if they can solve the issues with the gun it will miss its primary economic rationale and be canceled.

Scott Kenny said:
Don't the L7/M68 105mm tank guns use copper driving bands? The HEAT rounds do 1200m/s.
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I'm pretty sure M456A2 uses a nylon driving band but that's been the normal since the 1980's at least.

Scott Kenny said:
Had an odd thought: Two section barrel, breech end is rifled and muzzle end is not. If your propellant burn is slow enough, that might let you keep using copper driving bands because the shell isn't doing more than 1000m/s until the smoothbore section.
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A smoothbore would be best but that would preclude backwards compatibility, which makes the 155mm superfluous.

Mixing the barrel provides no benefit. It's just a tube. They thought they could get away with copper driving bands because they are a bit silly and don't know about high velocity copper driving band issues.

ERCA is in a bad place since it's already missed a deadline by a year and now BAE is showing off a L52 M109A7 at AUSA the year the M1299 was supposed to IOC.
 
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Kat Tsun said:
Mixing the barrel provides no benefit. It's just a tube. They thought they could get away with copper driving bands because they are a bit silly and don't know about high velocity copper driving band issues.

ERCA is in a bad place since it's already missed a deadline by a year and now BAE is showing off a L52 M109A7 at AUSA the year the M1299 was supposed to IOC.
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The Paris gun used a mixed tube, and we have much better control over burn rates these days. It'd be just this side of trivial to make a propellant charge scheme that allowed copper driving bands through the rifled part of the barrel and continued accelerating the shell once the shell left the rifled portion of the barrel.
 
Scott Kenny said:
The Paris gun used a mixed tube, and we have much better control over burn rates these days. It'd be just this side of trivial to make a propellant charge scheme that allowed copper driving bands through the rifled part of the barrel and continued accelerating the shell once the shell left the rifled portion of the barrel.
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The point is that it's supposed to use older types of shells and require minimal development time.

Which is why it's an M256 breech mated to the already developed XM351 from the M777ER. I believe this itself comes from some weird prototype from the 1980's ultimately, which is why it was rapidly developed and prototyped. A mixed rifled/smoothbore tube is incompatible with ERCA's development because it would require fabrication time. Bad for a program which is running on 5 years development time. If you're going to change it, you'd make it a 203mm or 175mm and a smoothbore, if you want it actually work. But because the point is be very quickly developed and deployed and backwards compatible, neither would happen.

The original plan was to have ERCA IOC with first unit stood up in 2024. It now looks like that might need to be pushed into 2025, if not 2026, and by then, GMLRS-ER will be in service and broadly invalidate the ERCA requirement entirely, which means it would never reach mass production.

ERCA has a greater than even chance of not making it out of development though, at least at this point, and had a slim chance of making it to production to begin with. Now that BAE is pulling more things from FMC's boneyard they probably see the writing on the wall. The GAO denied a one year extension on ERCA a while back because it missed its deadlines, but if it doesn't miss anymore it will on track to meet the IOT&E sometime next August and sometime in October or November '24 hit IOC.

ERCA will likely be canceled sometime in April or May of next year when the MTA comes up to review by DOD.
 
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Firefinder said:
That called Probert Rufling after the BRIT Colonel Probert who used it on the post WW2 super AA guns they fucked around with. Do believe one of the 4.5 inch guns had that set up. Which allowed the gun to smack things up to 50,000 feet.
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The Mk 6 3.7" gun used it, and entered service during the Second World War.
 
I believe the XM907 is based on the XM282 155mm gun designed for the 1980s Howitzer Improvement Program.

There have been several attempts to put 52-calibre guns on the M109 chassis, the most recent being the M109-52, but also things like the M109A6+ International Howitzer in the early 2000s.
 
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Yes it is the XM282, I simply forgot the designation. It may only have been used in the very earliest tests AIUI, or on the M777ER. Given only five years to develop the gun from nothing to initial fielding readiness, there isn't much wiggle room for slippage there, or any new development.

TomS said:
ERCA doesn't have to use the super charge all the time, though. At lower charges it shouldn't be significantly worse that standard guns, should it?
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It doesn't have to, but it's expected to, because without supercharge it would just be M109-L52. It was built with the expectation to be a 175mm-type field gun, with some capacity to use conventional howitzer ammunition and MACS, the latter mostly in permissive environments and emergencies.

Once they found out copper bands hate going fast, that's when the problems began to mount beyond a 5-year MTA. It would likely need a one or two year extension to make it work properly, and then it would require semi-constant modification for a few more years to work out the kinks, and maybe it would be functional around 2030 if it just kept getting funding.

ERCA is currently on track to meet its IOT&E and IOC goals around this time next year (October-ish t. Wikipedia), but the 5-year MTA review will come up before that, as I think that comes up in September. If it survives it will be very skin of the teeth since DOD already axe-murdered the waiver request made back in November 2021 for a year extension. They blamed COVID but in reality it was the driving band problem I think.

That's assuming no other slippage happens.


GAO talks about it in here in a few places.
 
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Kat Tsun said:
The point is that it's supposed to use older types of shells and require minimal development time.

Which is why it's an M256 breech mated to the already developed XM351 from the M777ER. I believe this itself comes from some weird prototype from the 1980's ultimately, which is why it was rapidly developed and prototyped. A mixed rifled/smoothbore tube is incompatible with ERCA's development because it would require fabrication time. Bad for a program which is running on 5 years development time. If you're going to change it, you'd make it a 203mm or 175mm and a smoothbore, if you want it actually work. But because the point is be very quickly developed and deployed and backwards compatible, neither would happen.
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Right. The M777ER with the two piece barrel as prototype. You keep the first half of the barrel rifled, and work the propellant so that the shells don't exceed 900m/s in the L26 (or whatever length it actually is) rifled barrel. But the propellant is still burning, so you get the shells up to 1500m/s or whatever in the unrifled second half of the barrel. Problem solved, though you do need to deal with aligning a two piece barrel that's meters long.
 
Scott Kenny said:
Right. The M777ER with the two piece barrel as prototype. You keep the first half of the barrel rifled, and work the propellant so that the shells don't exceed 900m/s in the L26 (or whatever length it actually is) rifled barrel. But the propellant is still burning, so you get the shells up to 1500m/s or whatever in the unrifled second half of the barrel. Problem solved, though you do need to deal with aligning a two piece barrel that's meters long.
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Again, the actual solution would be a smoothbore at that point.
 
Yes, I'm sure the engineers thought of that over lunch. Maybe even a few times. Unfortunately, ERCA has a massive charge that kicks the shell up to about 900-1,000 meters per second starting from when when it engages the rifling, and exits the barrel at slightly more than 1,100 to 1,200 meters per second, so that would not work. The driving band would be destroyed partway through regardless.

The nickel driving band was developed mainly to survive that initial impulse. Naturally this puts great stress on the rifling itself, and ERCA might last about 150-200 rounds in combat before needing a barrel change, which means you will need to carry extra barrels and change them about once every day, or sometimes more.

Being backwards compatible is what makes ERCA unworkable in the first place, though. Given it has a tremendous impulse, it's doubtful a half rifled half smoothbore barrel would work, and it's extremely unlikely this could be developed in 5 years anyway. ERCA was supposed to be fielded this year. The initial MTA was a 5 year development from 2018 to 2023. It was not granted a MTA extension by the Undersecretary of Defense A&S and now it is very likely going to be canceled when it comes up for review next year.

For ERCA to be developed rapidly, actually work, and get fielded, it would need to incorporate a new type of ammunition. A smoothbore would eliminate the main source of the gun's trouble: the rifling wear and driving band issue, not appreciably increase its complexity, and be fieldable in about the same amount of time. You could also increase the bore diameter to like 180mm to reduce the need for ultra high pressures, too.

If M109L52 can be fielded about as rapidly, it will prove to be a greatly superior weapon. The Dutch and Germans used the Pzh 2000's in Afghanistan fairly effectively, so an M109 with the Pzh 2000's gun and autoloader would be great for Artillery Branch. It'll hit the same 70 km range that ERCA is supposed to anyway.
 
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No, you do NOT have the shell doing 900m/s when it touches the rifling, unless there's an immense lede of unrifled barrel because you're not using the full chamber length because you're not using the supercharge.

Ain't how it works.

Shell is doing ~300m/s for the first couple inches of rifling, and will continue to accelerate for the milliseconds that the shell is inside the barrel. Else cutting down gun barrels wouldn't cost you any velocity, and using longer barrels with the same charges wouldn't gain you any velocity.
 
XM-1155 SC
When you don't feel Like buying Vulcano but want the abilitys of it
 

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kqcke for you said:
XM-1155 SC
When you don't feel Like buying Vulcano but want the abilitys of it
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Range of the 1155 is aiming for greater than that of Vulcano-155. Much like the Army possibly falling back on 109-52 if ERCA itself can't make it, Vulcano will remain a fallback option if 1155 fails to reach production.
 
Moose said:
Range of the 1155 is aiming for greater than that of Vulcano-155. Much like the Army possibly falling back on 109-52 if ERCA itself can't make it, Vulcano will remain a fallback option if 1155 fails to reach production.
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Still Vulcano gives you around "80%" of the capabilitys for Just "20%" of the price and you could even use IT across Services with the 127mm Vulcano for the Navy. And there is a Userbase already there Happy for everyone jumping on it
 
The Army is looking at guided range (with GPS degraded/denied) performance out to 150 km against relocatable and imprecisely located targets. If Vulcano can achieve that 20% of the cost of the other options, I am sure it will do very well in the competition. Worth noting here that we have yet to see the "Ramjet Excalibur" enter testing. Raytheon is the fourth team partnered on the XM1155 with their collaboration with TNO and also pursuing a ramjet solution.
 
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155mm Vulcano is Said from.bae to be 100km+ Out of ERCA which is around 2/3 of the range and the cost of Vulcano was between 70 to 150k $ in 2021. Now we dont know how expensive XM1155 is but it guess it will be in the same price range.
 

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80 and 20% are more of an metaphor then a real Number but If we take into Account the Money that is invested in the development im Sure you could buy mutch more Vulcano rounds for the same money
 
kqcke for you said:
155mm Vulcano is Said from.bae to be 100km+ Out of ERCA which is around 2/3 of the range and the cost of Vulcano was between 70 to 150k $ in 2021. Now we dont know how expensive XM1155 is but it guess it will be in the same price range.
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So it lacks the range that the Army is looking at. What type of seeker is it equipped with? GPS denied/degraded performance? So they could enter it in the competition and see if they even qualify or they could ask the US Army to cancel the entire XM1155 program and buy something that may possibly not meet the needs. If the Army is willing to do that, they can even skip buying the Vulcano alltogether and introducing a brand new round into its inventory. They can keep watering down the requirements until the Excalibur is able to meet them and just buy that.

kqcke for you said:
80 and 20% are more of an metaphor then a real Number but If we take into Account the Money that is invested in the development im Sure you could buy mutch more Vulcano rounds for the same money
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We don't really know the cost of the XM1155 (imposible to know) or that of the Vulcano that can meet at least the lower range of the requirements, so it's all just a WAG. Of course it is always possible to save a lot of money by watering down requirements to a point that allows you to buy a non developmental item. But then that's what the requirements oversight process is for and determining that a material solution is worth pursuing as R&D and the long term need justifies that pursuit at cost. XM1155 would have to do that once they select it for EMD.
 
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bring_it_on said:
So it lacks the range that the Army is looking at. What type of seeker is it equipped with? GPS denied/degraded performance? So they could enter it in the competition and see if they even qualify or they could ask the US Army to cancel the entire XM1155 program and buy something that may possibly not meet the needs. If the Army is willing to do that, they can even skip buying the Vulcano alltogether and introducing a brand new round into its inventory. They can keep watering down the requirements until the Excalibur is able to meet them and just buy that.



We don't really know the cost of the XM1155 (imposible to know) or that of the Vulcano that can meet at least the lower range of the requirements, so it's all just a WAG. Of course it is always possible to save a lot of money by watering down requirements to a point that allows you to buy a non developmental item. But then that's what the requirements oversight process is for and determining that a material solution is worth pursuing as R&D and the long term need justifies that pursuit at cost. XM1155 would have to do that once they select it for EMD.
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Glr can have Sal, a IR Sensor was there for the 127mm Version, i don't now how it perform in GPS Denise/ degraded can operate, Like I said you get 100km+ maybe even more If possible but as i Said you get around 80 of what you want with Just 20% of the "cost". 80/20 rule. I mean it isn't a true xm1155 but If you want that capability today and can't wait until next Week then you Vulcano is the best solution from my Point of View.
 
Scott Kenny said:
No, you do NOT have the shell doing 900m/s when it touches the rifling, unless there's an immense lede of unrifled barrel because you're not using the full chamber length because you're not using the supercharge.

Ain't how it works.

Shell is doing ~300m/s for the first couple inches of rifling, and will continue to accelerate for the milliseconds that the shell is inside the barrel. Else cutting down gun barrels wouldn't cost you any velocity, and using longer barrels with the same charges wouldn't gain you any velocity.
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You're using the supercharge if you're using ERCA. That's why it exists. The MACS compatibility is just a nice thing to have.

It's a gun, not a howitzer, but it's technically a howitzer, because it has zonable charges. Not that the crews would use them in practice.

The shell hits the rifling pretty hard, and the propellant is pretty hot, so a half rifled barrel won't do much for it in this regard. The main erosion areas are the freebore and leade, after all. Last I checked, the Paris gun had both. ERCA is essentially a tank gun, so its barrel life is comparable to 2A46, roughly speaking. As I said it might last 150-200 EFCs in practice, which in real terms is about a day or so in medium-intensity combat, and less for high-intensity. If you tried to use ERCA's shells in a Paladin you'd get similar results.

Without the supercharge, you'd just buy a L52 for Paladin and use copper banded shells. The long range shell technology might get recycled into a new Excalibur-type shell for the M109L52 if/when DOD decides to buy that to fill the need for longer range guns for the BCTs. If it goes with ERCA it will just get a sort of vaguely mediocre piece that can outshoot anything in the world for all of about 3 or 4 hours until it needs to swap barrels.

If you wanted ERCA to work within the MTA program schedule, you'd need to lose the rifling or lose the supercharge. Neither is a good look in DOD's eyes. The main business case was partly "we can use old 155mm shells" which was wrong, and necessitated the rifling, and "we can shoot very far", which was true, and necessitated the very hot supercharge.

That said, if DOD approves the ERCA program for another 12 months next year it might survive to see service, but they didn't grant the year waiver back in 2021, so it has a better than even chance of getting canceled when the MTA comes up for review. MTAs have strict 5 year schedules because DOD wants to avoid pointless boondoggles like Littoral Combat Ship, Future Combat Systems, and Comanche in the future.

If it can't be made in 5 years, or less, it ain't worth making nowadays. Which makes sense when the last major procurements took 10 to 30 years to produce half a dozen broken prototypes or worse. ERCA is shaping up to be one of those broken prototype programs like AGM-183 ARRW. The technology used in stuff like XM1155 will probably be reused in new ammunition for the M109s eventually, even if ERCA survives.
 
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What a shitshow. If they return to 155/52 which had been considered back in the late 80s after over 30 years...
 
Kat Tsun said:
You're using the supercharge if you're using ERCA. That's why it exists. The MACS compatibility is just a nice thing to have.


It's a gun, not a howitzer, but it's technically a howitzer, because it has zonable charges. Not that the crews would use them in practice.
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You got it backwards mate.

The Supercharge is the nice to have thing, not the MACs.

As is the 58 cal has bout a 5 km range increase over the 52 on per charge/shell average WITHOUT the supercharge.

And Artillery, even gun types like the 52 and 58, do not use full charge all that often.

Most of the time they are using Charge 4 to 6. Cause the big charges EAT barrels period no matter the gun for the same reasons. So to ensure that the gun has decent life they reserved the use of the big charges like 7 or 8 for times when its actually needed.

Thats been the Standard for well ever.

Like the last time the US had a gun in this performance band was the M107 175mm gun. Which was a 60 calibef beast of 40km range when using all 3 of its charges.

But normal use, even after the A2 barrels became standard, had it often firing only 2 charges to save on barrel life.


So yes the crews WILL be using the charges in practice and not the supercharges.
 
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kqcke for you said:
Glr can have Sal, a IR Sensor was there for the 127mm Version, i don't now how it perform in GPS Denise/ degraded can operate, Like I said you get 100km+ maybe even more If possible but as i Said you get around 80 of what you want with Just 20% of the "cost". 80/20 rule.
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So it does not have / has unknown GPS degraded/denied performance, and requires designation in an area of battle where the Army requires the round to perform within a GPS, Comms and aviation denied or degraded environment. So all it really has going for it is its range of 100+ km meaning that they can make do with it by shaving off around 50 km from the requirements of the program and other requirements for seekers, and other attributes. They might as well chip some more range away and make do with the Excalibur since that would be a lot cheaper given they would avoid the cost of integrating a foreign round which they do not have in inventory.

I mean it isn't a true xm1155 but If you want that capability today and can't wait until next Week then you Vulcano is the best solution from my Point of View.
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The XM1155 is not a "now" requirement. Its a future requirement which is why it is still in S&T funding with the round itself being competed, along with separate S&T research streams in the field of seekers, and warheads suitable for this future application. Given what the Army has published in terms of collective research around it and similar future capabilities, it really brings together attributes not seen elsewhere hence its still in S&T as opposed to advanced EMD.
 
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kqcke for you said:
80 and 20% are more of an metaphor then a real Number but If we take into Account the Money that is invested in the development im Sure you could buy mutch more Vulcano rounds for the same money
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It's a pretty well tested rule of thumb, honestly. 80% of the work to get to the target ability will take about 20% of the total effort. The last 20% will take up the remaining 80% of effort/funding/etc.
 
Kat Tsun said:
You're using the supercharge if you're using ERCA. That's why it exists. The MACS compatibility is just a nice thing to have.

It's a gun, not a howitzer, but it's technically a howitzer, because it has zonable charges. Not that the crews would use them in practice.
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Unlikely.

The classic artillery rule was 1/3-2/3. If the targets were within 1/3 of max range, time to up stakes and move back. If the targets were outside 2/3 of max range, up stakes and get closer. This applied to the 175mm, the 203mm, the 155mm, and IIRC even the MLRS and HIMARS.

Which means that only the rare times will you use the supercharge for spreading hate and discontent at 100km. Otherwise, you're doing all your shooting between 33-67km.
 
bring_it_on said:
So it does not have / has unknown GPS degraded/denied performance, and requires designation in an area of battle where the Army requires the round to perform within a GPS, Comms and aviation denied or degraded environment. So all it really has going for it is its range of 100+ km meaning that they can make do with it by shaving off around 50 km from the requirements of the program and other requirements for seekers, and other attributes. They might as well chip some more range away and make do with the Excalibur since that would be a lot cheaper given they would avoid the cost of integrating a foreign round which they do not have in inventory.
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I don't know the seeker requirments but it could complete them. We will See what xm1155 can do and If it may be would have been a good Idea to just take Vulcano instead....
 
What type of seeker has it demonstrated 155 mm capability with? XM1155 is basically a precision missile with the ability to find and prosecute high value (armor, IADS etc) targets at up to 150 km range with minimal or no designation and in a very GPS and comms challenged environment. This is why the entire effort, from the basic munition, future seeker technologies, and even warhead (there is a huge pressure on WH performance given the limited volume available to it given constraints imposed by electronics, propulsion, guidance and other competing priorities) currently sits in the S&T realm because most of these are at quite low tech and mfg readiness levels.

If you are going to claim that an in-service off the shelf system already exists that can meet that need than you need to provide specifics. If your argument is that they should continue to water down requirements until an OTS solution is eligible then someone can continue on that train of thought and propose continuing to water down requirements until existing Excalibur and Excalibur S rounds meet the need.

From a US Army perspective, there is a recognition that this is a legitimate and approved future need and that it needs quite a few technologies to mature, hence the entire program is sitting in the LRPF S&T books and is going to take most of this decade to mature and validate technologies and ultimately field this capability. Between now and then, they have plenty of other things out there including newer rounds, Excalibur S and even Excal HTK that they are exploring.

kqcke for you said:
I don't know the seeker requirments but it could complete them.
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I don't know the cost of the future XM1155 but it could come in at half the cost of the Vulcano.
 
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