Warhammer 40K Imperial Guard force to beat an Armored Brigade Combat Team

[JagerIV]

What sized 40k force would you say would have a 50/50 chance of winning against an American Armored Brigade?

A Armored Brigade Combat team has roughly 5,000 men, with 87 Abrams, 152 Bradley IFVs, 18 M109s and 45 armed M113, and roughly a 1,000 infantry.

Engagement is roughly a meeting: Imperial guard is dropped from orbit, and then the Brigade maneuvers to intercept the Guard forces on advance to target. Your goal is as an Imperial planner figuring out the minimal viable force to 50/50 such a fight knowing that an intact Brigade is the level of resistance in the area.

As a twist/extra challenge, try optimizing on cost/tonnage as well! Limited to the following units, to keep things relatively simple: if more clairifation is needed, I may add more.

Unit	Cost	Mass (shipping)	Weapon	Cost/round
Levee Infantry	$5k (1k equipment, 4k personnel)	250 kg	Autogun	$0.10
Guard Infantry	$150k (25k equipment, 125k personnel)	1 ton	Lasgun	$0.01
Storm Infantry	$1m (100k equipment, 800k personnel)	3 ton	Hellgun	$0.05
Leman Russ Tank	$2 million	100tons (60t tank)	150mm L/20 Cannon 75mm LasCannon, 1 MJ 2x heavy Bolters (25mm)	$5k (50kg HE) $20k (50kg penetrator)
Chimera	$1 million	50 tons (40t vehicle)	Multi Laser 1 heavy bolter (25mm)
Basilisk	$1.5 million	50 tons (40t vehicle)	150 mm L/40 cannon	$5k (50kg HE)

 

[Husky_Khan]

This is a good idea. We should have a Batchall style format where you create an opposing force and propose the bare minimum you feel is needed to defeat them based off an existing army list or somesuch.

 

[The Whispering Monk]

Well, let's consider the opposing forces.
The tech gap is simply ridiculous between the two forces. A single Leman Russ is likely able to handily destroy a company of Abrams. I don't even know if an Abrams can penetrate the armor on a Leman Russ. Maybe sneak the round in the turret joint? Probably generate a few mobility kills. For the Bradley and other local V's...maybe ATGMs are useful, but I kinda doubt it against anything heavier than a Chimera, even then I'm not sure it'll penetrate.

Lascannons, Meltaguns, hell, even plasmaguns will likely punch through any armor we have. Bolters of any type likely punch through everything but MBT armor.

Lasrifles will probably ignore anything but ballistic plates, even then, I'd hate to be on the wrong end of that thermal exchange as it will likely put the soldier out of commission anyway.

So...open engagement means the locals are screwed. Probably see loss ratios as high as 20:1 if not 50:1 in favor of the IoM forces. In an urban environment...well, IoM forces have never been shy about civilian casualties so the place gets wrecked, but they still win with some more casualties.

 

[Crom's Black Blade]

I'd need to know what regiments am I drawing from? Are these all Cadian shocktroops with their integrated armor or is it a random grab bag where armor, infantry and artillery not only are they not organic to each other but may come from totally different planets/cultures. As well are these green units or are they veterans?

But if you want my initial predictions, this conflict is going to go as well for the Imperium as you'd expect a pesudo-Soviet style "we have reserves" organization with a heavy focus on top-down command and firepower to go. Which is to say poorly.

At almost every level, except maybe, raw brute firepower they'd be at a disadvantage. Squad to Squad the IG seems more modeled after WW2 armies with squad support weapons tending to be big heavy machine gun affairs like the lascanon and instead having Guardsmen relying on the lasgun with has a very variable rate of fire. In the book "Imperial Glory" they're depicted as almost musket-like with the Guardsmen therein fighting as if they're British Redcoats with volleys while the standard M35 M-Galaxy pattern is listed as having only a cyclical firing rate of 220 rounds per minute while the M-16 assault rifle has a cyclical fire rate of 700-850 per minute with weapons like the M249 light machinegun being capable of higher rate of fire. So during any engagement with equal forces the Brigade is going to be throwing a lot more shots than the IG which means far more likely they'll hit their targets.

And just like their rate of fire, Lasguns are variable in their stopping power. There are references to them blowing off limbs or incinerating organs and other times we're told sandbags are effective barriers to them or we get a scene like this:

"Do your duty without hesitation, free of all doubt, and when those ugly green bastards come charging over the snow, drop them with a lasbolt to the brain, and buy us all another day of righteous service in the Imperial Guard!”
A searing volley of las-bolts blazed from the trenches, each shot slicing through the air with a distinctive hiss-crack. Scores of charging greenskins howled in agony and fell clutching their faces.
“Fifth Company, fire at will,” voxed Sebastev. “They do not get to the trenches. Do you hear? Fire at will!”
Troopers to left and right opened up on the orks as they sped nearer, carving black wounds into the wall of green flesh. Lieutenant Kuritsin scored a masterful headshot that put one of the monsters straight down. But, while all this las-fire would have obliterated an army of men, the ork charge barely slowed. Las-bolts could cut and char, but they lacked the raw kinetic punch of solid rounds. The orks shrugged off anything that wasn’t crippling. The battle-lust burned bright in their red eyes.
Sebastev brought his bolt pistol to bear on a massive ork charging straight towards him. He slowed his breath, took aim, and squeezed the trigger.
The gun kicked hard, and hot blood misted the air where the monster’s head had been. The heavy body ran on, legs still pumping, muscles executing the last orders from an absent brain. Sebastev watched the headless body snag on a tangle of razorwire, ripping open with a red spray before it tumbled down into the trench.
If the first wave of orks had looked large and fierce, they were mere youths compared to the dark-skinned brutes that now swarmed over the snows. Their overlong arms bulged with muscles swollen to unnatural proportions. Some wore crude suits of armour strapped or bolted together from plates of scrap metal and leather. Barring a direct headshot, a lasgun wouldn’t do much damage to them, short of making those plates scalding hot. But orks didn’t care about superficial burns when the battle-lust was on them. It just made them mad.

Where armor made of "scrap metal and leather" is impervious to a lasgun shot which can only "cut and char" organic flesh. So examples are a mix-bag to say the least.

As for armor things become even more lopsided. A Leman Russ off-road speed is officially 21 KPH and 35 KPH on-road which is comparable to a Sherman tank. An M1A2 Abrams off road speed is 40 KPH meaning the brigade could engage, shoot and then disengage and the IG could do little about it. This is further compounded by the Abrams boasting a computer assisted targeting system as advanced, if not more so, than anything you're going to find in a bog standard Russ which frequently is depicted closer to a WW2 tank in operation or, if we go by the old Imperial Armor books, like a WW1 tank in terms of heat and engine noise.

The Abram as also equipped with thermal imaging for night vision fighting, something I don't think I've ever seen a Russ posses.

And depending on which source you want to look at, IG armor may top out at the equivalent of 300 millimeters of conventional steel in which case the Abrams 350 mm+ equivalent of steel is likely to make them Baneblade like monsters to engage.

 

[JagerIV]

This is a good idea. We should have a Batchall style format where you create an opposing force and propose the bare minimum you feel is needed to defeat them based off an existing army list or somesuch.

Glad you like it. I was initially musing of about Guard vs earth in General, and realized that's wildly too large a topic to have a conversation on. Even vs the US is extremely large and would need way more qualifications. However, going down to Abrams vs a Leman Russ also doesn't quite work, because it turns into a purely technical question, when doctorine is important: a Leman Rus isn't as optimized to fight other tanks as an Abrams, but I get the sense Leman Rus really isn't optimized arround an anti tank roll anyways: the doctrinal roll is different.

Brigade seemed a good compromise where its small enough to be fairly bounded (no questions such as "how many more men can the US mobilize with 3 months warning?) but at a large enough scale doctrinal differences can be a major consideration.

Well, let's consider the opposing forces.
The tech gap is simply ridiculous between the two forces. A single Leman Russ is likely able to handily destroy a company of Abrams. I don't even know if an Abrams can penetrate the armor on a Leman Russ. Maybe sneak the round in the turret joint? Probably generate a few mobility kills. For the Bradley and other local V's...maybe ATGMs are useful, but I kinda doubt it against anything heavier than a Chimera, even then I'm not sure it'll penetrate.

Eh, I generally think of the Guard, especially with these weapon systems, as fairly low tech, with some elements of high tech. Which matches Imperium economics: large pools of very low human capital and development, with some islands of very advanced tech.

Leman Russ, Chimeras, and Basilisks I would see as generally not dramatically more advanced over all: mostly steel, maybe titanium equivalent construction, better engines but still basically gasoline (maybe all hybrids for the fuel efficiency and to power lasers and such).

I would thus probably put a Leman Russ as roughly comparable to an Abrams, but optimized for a different doctrine: more anti infantry and all round protection, less anti armor head on focused. As roughly similarly sized vehicles, I think their protection might be roughly equivalent: Abrams might even be slightly better protected from the front.

I think an Abrams can probably generally pierce a Leman Russ at useful combat ranges, while a Leman Russ with its large shell can reliably destroy an Abrams, though hitting it may be harder with a larger, potentially slower round and depending on how well maintained its targeting is.

Lascannons, Meltaguns, hell, even plasmaguns will likely punch through any armor we have. Bolters of any type likely punch through everything but MBT armor.

Lasrifles will probably ignore anything but ballistic plates, even then, I'd hate to be on the wrong end of that thermal exchange as it will likely put the soldier out of commission anyway.

So...open engagement means the locals are screwed. Probably see loss ratios as high as 20:1 if not 50:1 in favor of the IoM forces. In an urban environment...well, IoM forces have never been shy about civilian casualties so the place gets wrecked, but they still win with some more casualties.

Yeah, one thing I'm a bit unsure of is how powerful a Lascannon reasonably is: if its powered off the vehicle's engine, that suggests engine power in the 1 MW range, maybe 200-400 Kw output? With a rate of fire of 5 second, roughly the energy of a Sherman 75 mm gun, which is not a whole lot overall, but with a rate of fire of 12 rounds a minute as fuel holds out is quite respectable, and gives a line of site laser weapon capable of killing just about anything it can hit short of the front armor of a tank.

Other question then is bolter, specifically heavy bolter fire: 24 mm rounds I think a Bradley can generally survive, but I'm not sure about all round.

 

[JagerIV]

@Crom's Black Blade The level of quality is partially picked out by the person putting together the Imperium forces: Levee are the low quality, low motivation, poorly equipped troops. Commissar motivation is probably common, the men are probably drawn from primitives and convicts with middle school or less educations, etcetera. The Afgan army recruits. But, they're cost to the imperium is only calculated at $5,000 so expending an infantryman is equivalent to expending a round of artillery.

Marginal utility partially sets price: on the Imperium world of Space Afghanistan, what is the Imperium giving up by conscripting an Afghan peasant? Virtually nothing: he dies in an Imperial conflict rather than a tribal one, subsistence farmer who exports nothing continues to export nothing. People with virtually no marginal utility to the Imperium, and the Imperium has a lot of them.

If spending men is as cheap as spending artillery rounds, optimal force structures might change: You could have a squad of 6 Leman Russ for $12 million, or you could deploy 1,200 infantry. Against an Abrams squad, 1,200 trash infantry kept in line comissars or blocking forces may be a more cost effective means to counter the Abrams the leman Russ, as the Abrams run out of ammunition before sucessfully clearing out the infantry.

Guard level is more generic, well, guard level, were your human capital is better with at least a high school level of education (reading and math) and some motivation and familiarity with tech. And Storm is the elite.

 

[Crom's Black Blade]

Well for if we're doing Batchalls, not being the clanner, I believe there's nothing more honorable than victory. To that end I would attempt to achieve a 3 to 1 numerical advantage in an attempt to overwhelm my opponent. As such I would request the following:

1. 15,000 IG troops for a combined total cost of $2.25 billion
2. 261 Leman Russ tanks for a combined cost of $522,000,000
3. 197 Chimera troop transports for a combined cost of $197,000,000
4. 54 Basilisk mobile artillery for a combined cost of $81,000,000
5. On average 300 rounds of ammunition per infantryman for a combined cost of $45,000
6. On average 80 HE rounds per Leman Russ and 60 penetrator rounds for a combined cost of $417,600,000
7. On average 40 shells per Basilisk for a combined cost of $10,800,00

Total cost: $3,508,445,000 not including fuel consumed for vehicles or consumables by personnel

 

[The Whispering Monk]

1. On average 300 rounds of ammunition per infantryman for a combined cost of $45,000

Frankly, you can ignore this for most of the infantry, those armed with LasRifles. Don't need to pay for ammo as they can toss them in fires to recharge them.

 

[Crom's Black Blade]

Frankly, you can ignore this for most of the infantry, those armed with LasRifles. Don't need to pay for ammo as they can toss them in fires to recharge them.

Well them being equipped with energy weapons likely eases the logistical burden since they aren't carrying three hundred physical rounds but I'd still would want to drop with sufficient generators, storage batteries or Energon cubes so that each soldier could potentially fire that many shots without relying on fickle sunlight or campfires to recharge their weapons.

 

[The Whispering Monk]

Well them being equipped with energy weapons likely eases the logistical burden since they aren't carrying three hundred physical rounds but I'd still would want to drop with sufficient generators, storage batteries or Energon cubes so that each soldier could potentially fire that many shots without relying on fickle sunlight or campfires to recharge their weapons.

Every vehicle can charge them, and small power plants are standard kit for every IG regiment.

 

[Crom's Black Blade]

Every vehicle can charge them, and small power plants are standard kit for every IG regiment.

There are thousands of lasguns and a little over five hundred vehicles, that doesn't strike me as being practical not to mention that still requires fuel so the total cost would be the same.

As for the power plants, how many per regiment, what is there output and how much fuel do they consume?

 

[The Whispering Monk]

As for the power plants, how many per regiment, what is there output and how much fuel do they consume?

They're in the fluff, but I don't remember ever seeing any sort of ratio or TO&E on that type of equipment much less power outputs.

 

[Husky_Khan]

According to the Lexicanum Wiki which references some 40K book called the Imperial Munitorum Manual :

They have longer range and higher ammunition capacity than a Laspistol (the laspistol power packs having roughly 80 shots before depletion, compared to roughly 150 shots for a lasgun).

 

[JagerIV]

Frankly, you can ignore this for most of the infantry, those armed with LasRifles. Don't need to pay for ammo as they can toss them in fires to recharge them.

Power still isn't free. I forget where I calcuated this once, but I think I reached something along 1 cent per shot in energy costs, assuming refueling from gas vehicles. Can't find that now though, nor how much energy I assumed: I recall there used to be a neat laser penetration calculator, but can't find that either.

Might be worthwhile thing for me to return to sometime to re-calculate and explore my assumptions, but as @Crom's Black Blade numbers suggest, its probably a rounding error in this exercise. My own attempt, following higher command of the bare necessary force to this combat, as certainly hundred of other battles may be occurring on this world, and resources need to be prioritized.

Perimeter force
1: 10,000 levees. 50 million

These exist to make first contact, finding the enemy, and then pinning them down. a regiment of about a 1,000 spread into 30 man squads spaced a km apart gives a 30 km frontage of advance. 2 more on each flank can garrison the sides of the advance, up to about a 40 km advance, and 7,000 more for internal occupation, reserves, and manpower for need such as trench digging. Say, for example, placing a platoon to occupy and man a checkpoint at a crossroad.

These are not expect to advance against strong opposition or hold against a strong attach, but if there are minefields or ambushes in front, I want those suppress wasted on disposable infantry, not valuable tanks. And, if a breakthrough happens, I want internal hedge hogs in place, so when the first roadbump is hit, they come across a second one.

2: Overwatch

30 Leman Russ ($60 million)
30 Chimera ($30 million)
200 GI ($30 million)

Stationed about 1 km behind the tripwire forces, they provide prompt artillery fire (leman Russ) when the Levees encounter resistance, quick movement of specialists when special situations arrive, additional battlefield transport for levees when more than foot is necessary or medivac is available, and also as a blocking force when needed.

3) Rapid reaction forces

Leman Russ: 72 ($144m)
Chimera: 30 ($30)
GI: 200 ($30 million)

When a target arrives that can't be responded by overwatch, or overwhelmed with more waves of Levees, the rapid reaction force can be brought to bear.

4) Artillery

Basilisks: 36 artillery

Located at the center are 12 batteries (3 guns per battery) of Basilisk artillery. To be brought to bear on targets hopefully fixed by levee.

Totals

levee: 10,000 $50 million
GI : 400, $60 million
Leman Russ: 102, $204 million
Chimera: 60 $60 million
Basilisks: 36, $54 million
Leman Russ HE rounds: 10,000 $50 million
Leman Russ Penetrator rounds: 2,000 , $40 million
Basilisk HE: 10,000 , $50 million

Total: $568 million

This may be overly heavy: ammo may be generous for the mission. Might have been able to substitute more Levees for other expensive goods, like ammo (how many levees running with Krak grenades to kill a Bradley vs artillery pounding?)

Cost of the Leman Russ might be under predicted: $2 million might be closer to the cost of the tank itself, but a crew of 6-8 if they have to be Guard level to be worthwhile adds $1 million to the cost.

This would make Guard infantry more competive with just using more tanks: as it is, a leman Rus is $2 million, while a Chimera with a full load of 12 infantry is 2.8 million. Add in a crew valued at $1 million, plus I guess $0.88 million in ammo, gives each Leman Russ a cost $3.88 m to practically deploy, which might make Guard infantry more cost effective.

Hard to justify against Levee, if the levee can do anything useful, which mostly is blocking forces and finding the targets for artillery to destroy.

If the advance is on a 30 km front, between Leman russ and Basilisk is only about 5 guns per km. I'm not sure if that's super high or not. Also not sure if the US forces would attack across a broad front, or a narrow one.

 

[ATP]

Leman Russ are unable to fire when moving,so Abrams would have more hits.How many penetrate - it is another thing entirely.
Most important - communication.
USA have no problems with it,when imperial Vox could have.

Another thing - officers and commissars.Snipers would kill them in first hour of combat.And power swords would not help them.

 

[Crom's Black Blade]

Leman Russ are unable to fire when moving,so Abrams would have more hits.How many penetrate - it is another thing entirely.
Most important - communication.
USA have no problems with it,when imperial Vox could have.

Another thing - officers and commissars.Snipers would kill them in first hour of combat.And power swords would not help them.

I wouldn't expect the Imperial Vox units to have any particular problem. Hell with Combeads the Guard might have better direct communication than the Armored Brigade. I just don't think the Guard are organized in such as a way to exploit or utilize it.

Their entire way of fighting seems situated around a slower-tempo, less initiative-driven order of battle one which reminds me of the Inter-war French in a lot of ways. From Tanks being primarily used in more of an infantry support role to a greater emphasis on firepower than mobility or tactical flexibility.

 

[The Whispering Monk]

@ATP What on Earth makes you think the Leman Russ can't fire and move?

 

[Scooby Doo]

@ATP What on Earth makes you think the Leman Russ can't fire and move?

Probably it's horrible design lmafo!!

 

[ATP]

@ATP What on Earth makes you think the Leman Russ can't fire and move?

Official GW Books.In one of them,elite unit was elite,becouse tankers were capable of firing and moving.
Average units could not do such thing.
Forget title,as usual - but it was WH40 canon.

 

[JagerIV]

I wouldn't expect the Imperial Vox units to have any particular problem. Hell with Combeads the Guard might have better direct communication than the Armored Brigade. I just don't think the Guard are organized in such as a way to exploit or utilize it.

Their entire way of fighting seems situated around a slower-tempo, less initiative-driven order of battle one which reminds me of the Inter-war French in a lot of ways. From Tanks being primarily used in more of an infantry support role to a greater emphasis on firepower than mobility or tactical flexibility.

Doing the excercise myself does suggest somewhat why: if you have a pool of extremely cheap labor, the expense of a high tempo force is hard to do: like, my force had 10,000 trash infantry, which slows the rate of advance to a walk, but is just so cheap.

If it was all trash infantry, for $500 million I could do 100,000 infantry. Which if sufficiently motivated the Brigade probably just runs out of ammo before sucessfully chewing through.

I do think I might be understimating their overall cost though: I had some down time at work and did net present values on the soldiers, and $5,000 did turn out reasonable assuming the people would otherwise make $1,000 a year, and the Imperium got 10% of that. But, at @ATP reminded me to consider, getting anything out of the masses does require some level of officers. If Levee is 90% trash and 10% professional of, well, mainstream guard quality, Cost goes up to about $10,000 per troop.

Leman Russ I'm also thinking should be roughly $3 million, not $2 with crew and support equipment included.

But, slow tempo, infantry focused does make sense with the material available. Suggests at least to me a tercio style of warefare. Focused on absorbing blows, rather than delivering devastating ones. And makes some sense against likely opponents too: Imperial guard are likely not going to be more mobile for example than Chaos, Eldar, or Tau. They have more manuverability, and better ability to deliver shock. But, if they attack, blow through the first three defensive lines, get bogged down on the 4, and then surrounded as the breached lines reform behind them, well, their more maneuverable enemies are bogged down and surrounded, where artilley fire can now be productively brought to bear.

Similar logic beating a modern armored brigade: I think they're probably more manuverable than the guard unless I put together a very expensive unit. So, instead I have a big 30x30 km square advancing at a walking pace. If they harrass the parimiter, well, they're mostly killing completely expendable infantry. Those can be replaced to keep the slow advance, inflict virtual attrition on the US force as they get tired, disordered, and expend ammo.

If they attempt to hold ground, then they get battered down with artillery, and hopefully pinned by levee infantry encircling their position.

If they attempt to break through, their most organized, coherent and best rested attack is carried out against the first line of levees, leaving less capable attacks on later strong points, and if they don't take all of them, pushing in just leaves them surround in the tar pit.