# How to prevent powered armor from letting people carry bigger guns?

Oh yes, personal powered armors, such as MJOLNIR, are a staple of sci-fi. A sci-fi that disguises itself as fantasy needs to have some for the knights!

But, there is one thing I don't want to let it do, that is increasing encumbrance. If powered armor allows people to wield and shoot a Barret M82 like it was nothing, the whole point of finally letting armor catch up to firepower is lost.

So, powered armor can increase punching strength but won't allow you to carry that weight. Why?

• Soldiers can already carry the M82 fairly easily and can fire it from the prone position. Are you trying to make power armour-wearing soldiers less able to carry items than everyday soldiers, or are you wanting to stop them firing from a standing unsupported position, or both? – KerrAvon2055 Jul 10 at 1:23
• pretty sure lifting and punching use different bio mechanism or power or whatever it really called as. here a good link regarding it. – Li Jun Jul 10 at 8:39
• The point of the powered armor is that it can carry the weight of all that armor. If it didnt carry that extra armor you'll be carrying a gun far too big for its purpose and get killed just as easily by small-arms. So the extra encumbrance is all taken by the armor. Also we dont build tanks like the Mauser anymore because the loss of speed and maneuverability is more problematic than the extra armor can compensate for. So the extra weaponry and ammo would be too limiting for the power armor. – Demigan Jul 10 at 9:50
• Thing is, effective protection weighs much, much, much more than the bigger gun. A breastplate that can withstand the shot of a M82 is heavier than the M82 itself - the sci-fi powered armor is not a way of letting armor catch up to firepower unless you have extremely light unobtanium armor e.g. personal force fields that's not powered. – Peteris Jul 10 at 9:52
• Give it really tiny fingers. – Jason C Jul 11 at 15:31

You can't

The whole point of power armour is to carry more and carrying more means carrying bigger guns and if you had power armour, people would make bigger guns for them to carry.

Weapons soldiers use is limited by their ability to carry it around. Bigger weapons require a mobile weapon platform (ie wheels). Power armour is just another mobile weapon platform. It's stronger so can carry more and has more mass thus can handle more recoil from bigger weapons.

Any reason you come up with will have to be wishy washy such as a mega death cannon doesn't look as cool as a giant ass sword

There is no physical reason for power armour not to have bigger guns and it would defy logic not to give them bigger guns.

• Half the point. The other half is to have more armor that prevents other people from injuring or killing you with their bigger guns. – Mary Jul 10 at 12:25
• @Mary Carry more also means carry more armour. It's powered to carry more both guns and armour. – Thorne Jul 10 at 22:28
• This answer gets to the raw truth, but I would add that from a practicality standpoint, just being able to carry and shoot a Barrett M82 is only half of the equation- being able to carry enough ammunition to do anything useful with it is another matter entirely. Look up just how big those rounds and magazines are. Even if you can handle the extra weight, carrying a full combat load (240+) rounds of .50BMG loaded into 10-round magazines adds a prohibitive amount of bulk to your kit. The main reason most militaries use 5.56 rifles rather than 7.62 is to reduce the weight and bulk of ammo. – Catgut Jul 11 at 1:14

$$Strength \propto \frac{1}{Speed}$$

Also known as "Speed versus Torque".

Power armour loaded to slightly more than the typical soldier's kit allows you to sprint at high speeds without getting tired, leap 10 feet into the air, and punch like a charging bull.

Power armour can also let you carry a metric ton of weight (e.g. a 1979 Volkswagen Beetle). But, not both at the same time.

Think about it this way: a car can zoom along at 150mph, or it can drag a heavy trailer up a hill. It can't drag a heavy trailer up a hill at 150mph. The former requires a High Gear setting (high speed, low torque), the latter requires a Low Gear setting (low speed, high torque)

So too with your Power Armour. If the techs back at base have set it up for pure strength, then you have pure strength. The Force behind your punch is going to be on par with a freight train - if you can hit something. You'll be moving slowly enough that most people can dodge: $$Power = \frac {Force*Distance}{Time}$$. You can push really hard, and apply tons of pressure, but not fast enough to be worthwhile as a punch.

Similarly, you could probably use a Howitzer like a rifle - but, you can't aim it fast enough to track most moving targets close-up. And, at range, you might as well just put it down and use it normally.

• This is one of the reasons why destroyers where preferred for naval fire support on D-Day, they had the battleships, but a destroyer gun could get on target on a tank or bunker far faster than a battleship could, and still provide sufficient damage. You want the lightest gun that is big enough. – user1937198 Jul 11 at 10:42
• Yes, this is why we can't design cars that both go faster than people and carry heavier loads. – Pete Kirkham Jul 12 at 21:43
• @PeteKirkham Yes, this is why trucks go slower than sports cars. I mean, you could scale it all up, but then you don't have Power Armour, you have a tank or a mech. – Chronocidal Jul 12 at 22:03
• You have a mech when the operator's joints are no longer coaxial with the armour's. Powered exoskeletons already exist that are strong and fast enough to meet the OP's requirements, saying you can't build something which meets the requirement is like saying you can't make a car that goes faster than you can run and can carry more than you can. – Pete Kirkham Jul 12 at 22:07

It's not feasible

If powered armor allows people to wield and shoot a Barret M82 like it was nothing, the whole point of finally letting armor catch up to firepower is lost.

There is a quote: "If it works, it's already obsolete". It's inevitable that people would try to use find something to counteract the counteraction. For example, There is methods to block adblockers that blocks ad that blocks adblockers.

Unless...

The old solution to the problem just isn't available. Maybe at some point the size of the weapon would need to grow in size exponentially to have enough power to destroy the armor that gets carrying capacity linearly.

For example (all numbers completely imaginary): In the beginning in that case a armour would be destroyed by a 5kg gun, but allow for carrying 30kg. Later it would need a 10kg gun to be damaged, but only allow for 35kg extra capacity. Eventually these two points meets at, for example 100kg.The next iteration of armor would need a 200kg weapon to be damaged, but only allow for 110kg carrying capacity.

The guns would still get absurdly more powerful, but not enough to actually be useful against an opponent with a similar armor.

Or maybe the armor just happens to have some other pseudo-magical boons that counteract the weapons.

FORCE FIELDS:
All that armor is nice, but it's real virtue is in being a surface that conducts energy for personal energy fields that foil all those heavy weapons. These fields conform to the user's armor suit, and they are most vulnerable to contact with other armor, since the fields interact. So lasers refract, plasma scatters, projectile weapons are deflected, or bounce off, or need to hit incredibly hard, yet a fellow suited warrior with a conductive melee weapon attached to their suit can cut through it.

If the field is somehow psychic, even better - drone weapons and robots can't use them, and psychic power doesn't need a portable nuclear reactor.

That's not to say all those weapons don't work, or are ineffective. I don't think you can stop bigger guns, but they would need to be MUCH bigger to compete with force fields. The real goal isn't to take away the cool toys, but to bring back the good old fun ones - fists, swords, axes, etc.

The power provided by the armour is equal to the power needed to move said armour. In this case wearer still can't transport anything heavy, but they can deliver a good punch - high mass means high kinetic energy.

This idea was partially used in Fallout 1, where weight if the armour is higher than the bonus it provides - https://fallout.fandom.com/wiki/Power_armor_(Fallout). Though, strength stat increase meant being able to hold heavy weapons.

While some answers have delved into the mechanics of powered armour (speed vs torque, the effects on joints and so on), there are other consideratons which might come into play.

1. Logistics. You might not want to have a wide range of weapons, or single large overpowered weapons, but rather use the armour to allow the soldier to carry more of their existing ammunition and equipment. A typical loadout today is 10 X 30 round magazines for an M-4 carabine. What if the armour allowed you to carry 30 magazines, plus 3 days MRE's, 10l of water and other equipment? The purpose of the armour isn't to make a super soldier, but to enhance the ordinary soldier's ability to remain active in the field before linking up to the logistic support network.

A suit that lets you carry this makes more sense

1. Much larger weapons are possible, but the suit becomes a vehicle rather than armour. A HMG or automatic cannnon might be possible to mount on a suit, but you cannot fire it like a rifle, the offset torque will throw off aim, set up unwanted stresses and failure modes etc. Some sort of carriage and stabilization mechanism will be needed, which increases the size and complexity of the suit. Robot platforms with full stabilization make far more sense, since they can fire on the move.

OK, we're going to squeeze in through the basement window and then find the tunnel entrance....

1. Reality ensues. Soldiers already can carry extremely powerful weapons without any sort of augmentation today. A Javalin ATGM allows a soldier to attack a tank or even hovering helicopter with confidence at a range of 2500m or more. A soldier with a standard underbarrel grenade launcher can take out lightly armoured vehicles and fortifications at a range of 400m, and future "guided" grenades like the "Pike" can extend this to over 1000m. No amount of personal body armour will protect you if a soldier is firing something like a Javalin, and if powered armour becomes common, then anti armour weapons will become common as a counter-measure. That being the case, simple exo skeletons to allow more load carrying (see point 1) make far more sense

I'll see your armour and raise you a missile

Or, you could always issue some of these instead

JOINTS!

If you carry more weight, when you try to jump, the added weight will destroy the complex wired teflon joints.

If you try to move with more weight, the effective range is reduced, after all, the fuel cells can only provide this much juice.

Shooting a barret is done stationary. Leaping with 30 kgs more, will stress the knee and ankle joinst past the safe limit. Could be a moment of tension in your story.

If I carry a bigger gun but discard the rations.. maybe I can make it before I die of dehidration.

As an alternative: conventional weapons have simply changed.

Around the time of world war II all factions asked themselves the question of what caliber their weapons would need to be, and all 3 came around to the same conclusions for each caliber and their use. This because each caliber had a purpose in how powerful they needed to be at different ranges.

With the introduction of power armor we can also assume that metamaterials are introduced. If you can synthesize the strongest spidersilk available to spiders you can make incredible armor protection, and this is just one layer of your power armor. Graphene doped products, Diameme(1), converting the bullet impact into pressure inside a layer etc could all help make these armors extremely resiliant while weapons might still be prohibatively expensive. A railgun for example has problems at the end of the barrel where the forces expelling the projectile blast bits of the rail away with each shot, needing replacement soon.

The end result is that the conventional weapon is still an explosive charge meant to launch a bullet, but with a larger base caliber to wear down power armor and chip pieces away, bruising the internal structure until finally the armor or occupant fails. So your soldiers do carry a machinegun version of an M82, but are still less able to kill their opponents.

It's mostly the lack of real world experience of most game designers that causes what you see in games, which is why I seldom play them. Given my experience as a paramilitary contractor, i cringe at the sight on how wrong they get it. in one movie with soldiers in Science fiction, i cringed as I watched them do over 20 things that you just never do on the field.

I personally believe that manned platforms like power armor simply wouldn't be made, and instead humanoid war droids would be deployed instead. The biggest solution to MJOLNIR killing a normal human is to make the platform unmanned from the get go, and mass produce those. a battledroid can be mass produced whereas a human takes two decades to mature, and is irreplaceable. when a human dies, you're never getting him back---not even with cloning.

and to answer the question, humans wouldn't carry that weight, because they would never have the need to. Just send in your MJOLNIR based killers robots against the covenant and keep your virtually never ending flow of reinforcements coming against the covenant. superior technology or not, with an endless flow of reinforcements, the covenant would soon find their holy war untenable if not outright unwinnable in a period of a year to 17 months by my estimates. And it's how it would actually be.

generally, stories like halo usually have the Spartans to give something the audience could relate to, but it's far from how such a conflict would actually be fought. The UNSC would quickly phase out manned assets and start a crash program to replace them with unmanned versions the first battle things go south, and start investing in unmanned drones and warships like there is no tomorrow. Although the Spartan IIs would be in the picture, they would become the main bodies of drones based on their suits, and operate from semi-unmanned warships.

you halo fans may call me out on the above, but it's how in real life it'd go in all likelihood. in spite of of being outclassed in technology, the UNSC, once they go the unmanned route would crush the covenant under the weight of endless numbers.

as a matter of fact, that's how the Red army and the armies of the allies defeated the Axis powers in WWII: Numbers.

and with Halo and other games, it's just a story, and somebody's opinion. It's an opinion based best guess of what somebody thinks will work.

• While I agree on your conclusion, from the point of view of a government or organization, humans may be morally irreplaceable and whatnot, but they are actually easily replaceable (by another one) and they come free - you don't have to pay to build them, while every unit of unmaned robo-soldiers is \$1.5 billion a piece. An infinite number of droids requires an infinite budget. That's why the US Air Force does not have 5,000 F-22 fighters. – Rekesoft Jul 10 at 6:48
• Thats all true, but there are countless ways to make it make sense. Armours powered by psychic abilities, expandable humans that are cheaper in a grim dark future, clones and all kinds of other sience fiction stuff. So the real world doesn't really apply because most of the time it's a different or alternate world. – Lichtbringer Jul 10 at 9:23
• Actually, there's no point in making humanoid robots at that point. A remote-controlled quadcopter with a rocket launcher will probably do the job just as well and be much cheaper while retaining the reliability and smartiness of humans. On a side note, don't forget the fi in sci-fi. It has to be an interesting story/game. – AmiralPatate Jul 10 at 9:36
• Its a story-telling thing. A story about droney the drone just isnt as interesting as a human (modified as he may be) battling the odds and simultaneously being superior. This is why 100% of all science fiction is wrong. Especially the hard science fiction. But you know what? Its actually FUN when its wrong, as long as its consistent with itself. – Demigan Jul 10 at 9:53
• @AmiralPatate Depends on the purpose: as a peacekeeping force, a quadcopter murderbot is a lot less likely to be able to reassure and calm the civilian populace than a humanoid robot or, even better, a human in power armour. Your drones would be reminiscent of biblical angels: "B̬̜̰̱̣ͅe͏̩̦͕̯̮͎ ̳̩̬̯̼̩N̹̺̮̺͠ͅo̙̪̝̼͈̩͇̕t̢ ͖͓̭͡A̯͇̩̟̱ͅf̻rà̹̗̫͚i̵̜d҉̫̞" {Panicked Screaming Ensues} "I̵͈̹̟̦̹ ̮̜̣̬S̰̜̪̟ạ̴̥͚̤͍i͕d̯̥̤̰͉̕ͅ,̵̣͙͉ ̘̙́B̶̯̝̦ḛ̺͚̥͖̣͝ ̝̜͚̹̰̖N̼̤̬̖͟o̩͉t͙ A̭̬͙̻f̞̰r͈͚̬̥͜a̖͓ị̬̩͠d͚͎̩̺̙͇͇͢!̝̯͎͕̗" {Even more Panicked Screaming takes place} – Chronocidal Jul 10 at 10:12

Because the weight limit is still the person

It's kind of funny you mention MJOLNIR armor in your question, as HALO lore very specifically ties down the armor to SPARTAN soldiers because the armor literally will kill a normal human if they attempt to wear it. You can increase the power of armor, sure, but ultimately, there's a human inside that armor, which means that all the armor's weight is focused on the human. So, even if it can have a hydraulic punch that can dent a foot of steel, it still can't pick up significant weights or handle massive recoil without putting too much stress on the human wearing it.

It will probably still allow for the casual use of the M82 sniper rifle, but fortunately futuristic super-alloys is also a staple of sci-fi, so you can make the armor out of that and explain that they are now completely bulletproof.

• I was thinking that maybe carrying stuff depletes the armor's batteries faster... – Mephistopheles Jul 10 at 0:57
• This is simply not correct. You can design the armor as a powered exoskeleton, so that it puts as little force on the human as say operating large earthmoving equipment. – jamesqf Jul 10 at 3:27
• @jamesqf Its not really armor at that point though, is it? Might as well be a mini-mech. And while mini-mechs are awesome, there is somehow a distinction between mini-mechs and powered armor in soft sci-fi. – Halfthawed Jul 10 at 3:34
• @Halfthawed Insert running gag in Saint's Row IV where NPCs and Playa are arguing about whether the mech that Playa finds is a robot or power armor, until Playa comes across actual power armor in the last mission of the game. – Nzall Jul 10 at 9:40
• @Mephistopheles The battery thing would actually be a legitimate answer. – AmiralPatate Jul 10 at 10:13

In another question it was asked why power armour wasn't feasible. It's because firepower is incredibly high, making power armour too expensive and easily damaged to be viable.

To offset this, the power armour might have added several layers of protection. All the weight added to it does make a "normal" movement difficult to stop and thus incredibly powerful. A punch is something you don't want happening to you or equipment you own. Downside is that the motors are taxed to the max thanks to the weight. Any additional weight starts slowing it down, making only light and normal weapons feasible. If heavier weapons are carried, the armour gets so slow It's impractical or simply stops to function. Finally, the armour is still strong despite being at it's maximum power thanksto the weight. Possibly in the field the armour often accidentally crushes the weapons when the soldiers are in tense situations and they squeeze their weapons. This makes heavy weapons too risky to wield as they present a more hefty investment. Add to this that soldiers are often more panicky if the armour moves slow because of a heavy weapon they are more likely to tense up so hard the weapon breaks.

Up-scaling the weapon (including its weight, recoil and ammo load etc) means ups-scaling your power armor in the process - including its cost an complexity. You also rapidly reach the point where the weapon system being 'carried' by the power armor can just as easily be mounted in a normal fighting vehicle.

This means your armor has to have about the same mass as a fighting vehicle fitted with the same weapon but the vehicle will almost certainly have with a lower profile and be easier too conceal.

At the same time (if not before) you reach the point where your armor ceases to be 'worn' by the wearer and is instead 'crewed' by an operator or operators. Unless you are talking one shot 'fire and forget' systems most large weapons need a team to operate effectively for any length of time. This means you are not 'wearing' armor anymore but instead 'operating' a two legged fighting machine. And in almost all situations such a machine would be inferior to a wheeled or tracked opponent.

Recoil is the problem.

Weapons soldiers use are limited not only by the mass of the weapon, but also its recoil. See the XM109, an experimental version of the M82 which weighs only 33 lbs, but has an impractical amount of recoil - no matter how strong or weak you are, firing the weapon will just about knock you over. A strong but light suit of power armor would allow soldiers to carry huge weapons, but not actually fire them, since they still do not have sufficient mass to resist the recoil.

Weapons with large recoil must be mounted to a heavy chassis, or else the weapon will shoot itself backwards when fired - firing a tank cannon that's not mounted to something with the mass of a tank is a bad idea.

• Recoil is at best an engineering problem. You can for instance, just fire something in the opposite direction simultaneously to cancel it out. Or wait and find something to brace against before firing. Or even just be knocked over... who cares if the other guy is now dead. You get up and keep going. – John O Jul 10 at 15:04
• A soldier's ability to deal with recoil is limited by their ability to counteract the recoil. If power armor makes soldiers stronger, they are also better equipped to deal with recoil. Since bullet impact and weapon recoil scale equally (as stopping power is effectively equal to recoil, action vs reaction), that means that there is no upper limit on recoil management if you're already dealing with armor that can carry the improved weaponry. I.e. your answer would only apply if the soldier could not already wield that weapon, which makes it moot. – Flater Jul 10 at 15:14
• @JohnO This is very true, recoil can be reduced to allow for very large weapons. But a recoilless weapon will necessarily pack less punch than one that does have recoil, so at some point there's a tradeoff of power vs mobility. You can choose to give a recoilless heavy weapon to a soldier in power armor, or put an even more powerful version of that weapon with recoil on a vehicle with greater mass. Agree this isn't a hard limiting factor, but something to consider. – Nuclear Wang Jul 10 at 15:15
• @NuclearWang: JohnO isn't talking about a recoilless weapon, he's talking about managing the (very much existing) recoil of a weapon. Also, when you say "or put an even more powerful version of that weapon with recoil on a vehicle with greater mass", since there is no significant distinction between power armor and vehicles, you're disproving your own point by arguing that a vehicle can handle recoil that a power armor supposedly couldn't. Whatever technology a vehicle is outfitted with to handle recoil, so too can a power armor be outfitted with that technology. – Flater Jul 10 at 15:17
• @NuclearWang: You're missing the point that bigger power armor is heavier and likely has a bigger (literal) footprint, both of which tremendously increase friction. On top of that, you're still not accounting for any additional technology to further counteract or even completely negate recoil. Off the top of my head: reverse thrusters, recoil rifles, non-kinetic weaponry, or even a kickstand (which cannons have had for centuries) would all negate your recoil-based answer. – Flater Jul 10 at 15:23

You don't really need power armour to have a man portable, shootable 50 caliber. The gepard lynx does a great job at shorter ranges no power armour needed.

Lets assume you wanted to prevent real overkill - like a 30mm autocannon round. There's probably a few engineering constraints to consider, what static and dynamic forces involved.

Armour is static, and dosen't need you to suddenly handle a large impulsive force. A gun would. Even a way to improve punching strength would have lesser dynamic forces than a gun.

## The answer lies in why you need power armor to begin with

If your power armor is as hard to penetrate as a tank, then you need a gun as powerful as a tank's main gun to penetrate it. The problem is that this often means annihilating the entire area that your target is standing in as well. But in modern warfare, infantry is not used for annihilating a target, it is made for taking and holding key infrastructure. If you start running around with 130mm cannons inside of a command bunker or on the bridge of a starship, neither side will end the conflict in possession of the thing they wanted to take and hold, because the collateral damage would take out the thing you are fighting over to begin with.

This means your weapon designers will need to design weapons that not only can penetrate an inch of carbon nanofiber composite armor plating, but can do it without destroying everything around your target. This is where high-tech melee weapons will come into play. If your power armor has a claw that can exert thousands of tons of crushing force, or a fusion powered plasma blade that can superheat anything it touches to a 10,000K in a fraction of a second, then you start seeing weapons that will kill through the armor without having to worry about a single missed shot bringing the whole ceiling down on your head. Power armor infantry may still have crazy powerful cannons for when they get stuck fighting in the open, but once they have a roof over thier heads, it's time to "fix bayonetts" or whatever your future equivalent of that is.

Thorne's answer that wielding heavier weaponry is unavoidable is correct. However, there can still be diminished returns.

So, powered armor can increase punching strength but won't allow you to carry that weight. Why?

A very important distinction: I infer your interest is in limiting the damage output of the weapon, not its weight. Your question is built on the assumption that the only limiting factor in weapon output is what a soldier can carry, but you're subtly also relying on that increase in weight and power output scaling equally.

Your answer is found in making that weight/damage increase not scale evenly.

If increasing a weapon's damage output by a factor of X increases its weight by an even bigger factor of Y, that leads to needing a significantly stronger power armor to wield it, which in turn leads to a significant increase in defense (bigger than the damage increase of the weapon).

The logic is as follows.

1. I make a weapon that does X times more damage
2. This weapon now weighs Y times more (where X < Y)
3. We develop armor that is Y times stronger so it can wield this new weapon
4. This new armor can therefore wear armor plates that are Y times stronger
5. This armor's defense is Y times stronger, and since X < Y, the new weapon is less effective (against the new armor) than the old weapon was (against the old armor)

And the cycle repeats. If the weapon weight increase is not linear but exponential (for a linear damage increase in weapon damage), you can't even repeat this cycle too often because of the ludicrously strong armor you'd be required to develop just to wear it.

And that is, after all, the effect you're going for.

So while the improved damage output of weapon still increases, it doesn't increase enough to actually overcome the defense increase of the improved power armor itself.

To justify this, you simply need a civilization with better armoring skill than gunsmithing skill. Or you can rely on basic chemistry whereby the material used for armor gives you more bang for your buck than the material used for your guns.

Carry bigger guns? Why not. You have the extra capacity. You will be slow but sometimes that's worthwhile.

Fire bigger guns? Now that's another question. A bigger gun requires more stability while firing. A human-sized platform (ie. your power armor) can only provide similar stability to a normal soldier.

One real advantage is that you can ensure that the armor assists the soldier in providing better stability, but then you get something similar to what well-trained elite soldiers can do on their own. Still better, because you now have green grunts firing on par with elite squads.

Changing posture helps with stability, but again, the same for naked and assisted soldiers. But maybe, your armor has some stability-enhancing accessories, like a third leg that unfolds from your back on demand.

Still the size of the weapons you can fire reliably won't be affected much, even though you can

• Fire them better than you probably could, on par with the best soldiers
• Carry a much larger ammo load without dragging yourself down, so fire a lot more bullets
• Easily carry multiple alternate weapons of similar size, expanding the types of targets and ranges you can engage (Sniper rifle + Assault rifle + Submachine gun)

If we are talking about man-portable but not man-fired weapons, like portable mortars, you sure can go bigger if needed, but usually the extra capacity is better used for extra ammunition.

Reduce Accuracy

You can always say powered armor that allows great strength will reduce accuracy.

# You can't prevent M82s from being carried, but...

You can prevent them from being useful. Invent a high-tech reactive armor that completely negates conventional weapons. Next you need a high-tech gun that can get around said armor, but doesn't work near big hunks of metal (e.g. power armor).

The weakness of any power system is often it's controlling structure. I know there are other answers about weapon recoil, but no-one's mentioned the substantial noise and vibration that a heavy weapon tends to bring with it.
All you need is for the control systems of said power armour to be unable to resist the vibration - this would make the armour technically able to bear a heavy weapon, but rendered useless and immobile as soon as the weapon is fired. As a hint, if the armour system is a self-balancing humanoid (ie two legs, or anything else that requires a substantial balance) it will require a sensitive electric gyroscope to track it's orientation. (Admittedly you'd need a bit of license on this, as I know there are now some quite strong gyroscope systems used in military jets that can deal with vibrations of supersonic flight).

If this was the case, it would create an obvious weakness when the armour sustains a hit (unless it's being used against chemical, biological or incendiary warfare I suppose). The simple answer to that is to have flexible damping/insulation between the 'main frame' and the exoskeleton - flexible enough to absorb the shock of a hit, but also to render a heavy weapon useless if mounted on it either through inaccuracy or overall torsional weakness of the shock-absorbing system.

## Doctrine

At the moment, two of the largest armies in the world are contesting a region called Galwan Valley.

It might surprise you to learn that neither sides' troops are carrying firearms.

Despite both sides being nuclear powers, neither wishes this fight to escalate. There have been conflicts, and there have been casualties (people beaten to death with fists).

## How Does This Apply?

Limited conflicts, where one side voluntarily shows restraint, aren't new. It could be that politically use of powered armor to "keep our boys safe", but simultaneously limiting what they can do offensively is palatable to whoever is making the decisions.

## Institutional Inerta

Doctrine, design, procurement, and training can have a long lead time. So, if a prior administration commissioned the power suit as a restrained-conflict weapon, there's now institutional inertia keeping it that way, even if the current situation is different.