How well would a space marines weaponry fair against a modern battlefield?

[FancyDarcy]

I've been wondering how's useful weaponry space marines in warhammer really are. I mean, a rifle the size and weight of a AK 47, the power of a 7.62 x 54 round or more, and magazines that charge in fire and aren't too heavy sound great.

How useful would they in real life? I've read this numerous times on reddit, but there is never a fixed stats sheet and firepower, weight and capacity can be anything from "60 'pistol rounds' on low, half that on 5.55 x 45 rounds, and further halved for something even bigger to the weakest shot is comparable to a 30mm autocannon round and the strongest can topple mountains.

One of the biggest points people make is the versatility of the laser rifle, saying it can be a machinegun, a SMG, a shotgun, a rifle, or even a designated rifleman and possibly a anti vehicle.
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I've heard people saying the magazines can be used a grenades and you can bash someone over the head with the gun itself, although I guess modem US Army rifles are fragile, how useful would they be on a large scale? Are soldiers regularly engaging in close quarters combat with the enemy?

I wonder how quickly those magazines actually charge. I've heard that can charge under sunlight, how quickly though? A few weeks? What about inside a campfire? How easily can soldiers prepare a campfire in all combat scenarios?

[Zixinus]

Space Marines and even the Guard are generally highly wanked.

How good is exactly their equipment compared to real world military equipment depends on how you interpret data from various sources. The wargaming vs novel vs animation sources would vary for example. This is a big divider because if a SM can withstand small arms fire, then a radical change in tactics are called for.

Space Marines, Guard and others would fare well against more-or-less equivalent levels of real-life, Earth forces. They are designed to be powerful and superhuman soldiers after all. If you do a Battle-dome scenario with a X amount of real-life soldiers fully-equipped VS X or ,even X/2, amount of SMs TO THE DEATH? The SMs would win most of the time because they're gene-engineered superhumans with power armor and futuristic weapons designed to both withstand and kill things much stronger than humans. Even the Guard armor is supposed to be quite powerful.

I've heard people saying the magazines can be used a grenades and you can bash someone over the head with the gun itself, although I guess modem US Army rifles are fragile, how useful would they be on a large scale? Are soldiers regularly engaging in close quarters combat with the enemy?

Mostly irrelevant actually. Both WH40k and Earth forces have better melee weapons than magazines. Magazines are not meant to be weapons and if you are in a melee situation, there is a host of better weapons available than magazines. This includes not only actually issued weapons like bayonets (and the rifles themselves) but also tools like knives, shovels, hammers, etc. Melee still happens in modern warfare but rarely the decider, and when it does happen bayonets or knives are usually sufficient.

Sure, spare magazines can be used as grenades but do you know what would be better? Actual grenades. The biggest difference is that lasgun magazines could be recharged in the field, powersource provided. You can't manufacture ammo on the field for real-life weapons. You do not want to use one as a grenade if you can avoid it. Also, this is hardly a tremendous tactical advantage.

[Zixinus]

EDIT window:

SMs and such would win until they run out of ammo and fuel. So Imperium forces would dominate until the other realities of war would come crashing in. Such as being more quickly able to call in airstrikes or artillery. SMs in particular exist because of the whim of the God-Emperor and his fetish for gene-engineered superhumans. To question their cost-effectiveness would be heresy. They aren't just a military force, they are an entire realm of monastic orders with a large number of monks and cyborg-robots serving them. I doubt most SMs can do repairs much above obvious field repairs.

Melee weapons are not very important when you have humans with modern (or better) weapons fighting each other, because soldiers usually prefer to keep shooting at each other form the distance rather than rush in close enough for melee. That is not to say that they don't (particularly when the aggressor has good armor and more disciplined), but that is the tendency. WH40k forces often have various ridiculous melee weapons because several of their bigger enemies are melee-berserkers.

As for lasgun-versus-real weapons: lasguns are better. Remember that lasguns are only really considered weak when compared to the other more powerful Imperium weapons; and because often the enemies of the Imperium are much tougher than regular humans. Against humans, a lasgun is plentifully powerful.

The lasgun-as-all weapon is also an advantage but mainly because it ties into the general advantage of the weapons being rechargable. With SMGs and shotguns and whatnot you need to carry different ammo types. With lasguns, you can just change the power setting (unsure about the "shotgun" function but that's not important). Otherwise, there are variants of the lasgun that balance for accuracy or size like regular assault rifles.

[Eternal_Freedom]

I don't think you can compare a Space Marine force to a modern field army because that's not what Space Marines are meant to be. They're supposed to be the ultimate airborne shock troops from hell, dropping in when you don't expect it from space, killing a few vital targets and then moving on. They don't do combined-arms warfare the way the Guard do - hence why the best (non-Forge World) Space Marine tank, the Land Raider, is more of an IFV than an actual tank.

So if we said, say, "2018 US military vs entire Ultramarines Chapter," I'd bet on the Ultramarines, because the chapter comes with the necessary strike cruisers and battle barges (and air support) to support precision strikes from orbit. And as a non-Ultramarines Space Marines player, that hurt to say. Fuck you Smurfs.

If we said "Take just the 1,000 footslogging Marines/Terminators and sat them in a field with the 1st Armoured Division"...then I'd say it'd be a much closer call but I'd bet on 1st Armoured.

[FancyDarcy]

Note: I'm typing this on a phone,

Are there any official stats for the 40k laser rifle? I've seen the stats ranging from slightly superior to a normal M 16 all the way up to a man portable death star laser.

How useful is charging cells in a campfire? What kind of fuel would you use to stay a fire out in the sandy desert? Also, how hot does the fire have to be, and how long will it take even within a raging chemical fire? Surely it's not too useful if it'll take a deadly chemical fire and even then take a few days to fully charge.

The ability to be used as a melee weapon is actually claimed a lot on online debates.

For example, here are some claims of the superior firepower of the 40K space marines.

https://www.reddit.com/r/40kLore/commen ... h=d17afeda

In this example, the post is saying that a laser rifle is comparable to a .50 BMG round on its lowest setting, which is available in hundred rounds. The space marine tank, the demolisher has a large siege cannon which despite its short range, had more boom per shot and Is therefore more superior than every single MBT in every possible way. A single demolisher round could destroy a M1 abrams in a single shot, therefore making the MBT useless compared. However this is a very bold claim copinionated to a different claim on reddit.

https://www.reddit.com/r/40kLore/commen ... nt/du3cdnb

Here is another claim stating a more reasonable approach, a laser rifle has around 60 pistol shots, and half that for assault rifle shots. With more reasonable stats like this, how effective would a laser rifle be on the battlefield?

[bilateralrope]

Recharging lasgun cells in a fire damages the cells. It's something only done when the guardsmen are desperate because the usual methods of recharging them are unavailable. They prefer to charge them off a power source. Almost any power source, including the engines of their vehicles.

As for how powerful they are, WH40K fiction is seriously inconsistent on most things. I've seen examples of single laspistol shots ranging from exploding a human head/arm to only causing slight burns. Though the lower end examples are all from various underhives, so could be low quality variants.

For example, here are some claims of the superior firepower of the 40K space marines.

https://www.reddit.com/r/40kLore/commen ... h=d17afeda

In this example, the post is saying that a laser rifle is comparable to a .50 BMG round on its lowest setting,

Are you confusing lasguns with weapons used by space marines ?

Lasguns are only used by human forces like the Imperial Guard. The standard weapon of Space Marines is the bolter, a fully automatic weapon firing armor piercing rocket propelled grenades. Very different weapons.

[Simon_Jester]

I actually wouldn't be surprised if he's seen sources indicating that a lasgun can do .50 BMG-level damage (that is, blowing apart limbs and penetrating light armor).

The big question is, do lasguns have better firepower than modern infantry rifles? Or has the Imperium adopted them for the good and simple reasons that they're more accurate and effectively impossible to run out of ammunition, even when resupply is nigh-impossible?

[Elheru Aran]

I actually wouldn't be surprised if he's seen sources indicating that a lasgun can do .50 BMG-level damage (that is, blowing apart limbs and penetrating light armor).

The big question is, do lasguns have better firepower than modern infantry rifles? Or has the Imperium adopted them for the good and simple reasons that they're more accurate and effectively impossible to run out of ammunition, even when resupply is nigh-impossible?

More the latter. Though it should be noted that 'autoguns', basically 40K versions of M-16s, do exist in-universe; lasguns are just more common, I suspect largely due to supply line concerns. All you need to resupply lasgun-armed troops is a generator which would probably already be at any forward base, while autoguns require regular shipments of ammunition.

Re Space Marines specifically: one-on-one, their weapons are probably more powerful (with some caveats) versus modern equivalents. Boltguns for example are basically automatic grenade launchers with variant munitions available. The primary difference is range; overall they are not depicted as fighting at ranges much over, say, 100 metres. Note that the flamethrower is a common weapon for them; these are hardly long-range weapons.

This is largely due to their mission profile of shock assault; they are not geared for long range battles of attrition. That's what the Guard is for. Marines are intended to get in close to the enemy and swiftly crush them. Their vehicles reflect this as well-- cybernetic walkers with close combat and close range weapons, close-air-support flyers, high-speed antigrav vehicles for strafing, light tanks that are basically converted APC's, and a very heavy APC.

If you want a closer equivalent to the modern military, you want to look at the Guard.

[Jub]

First of all, you really ought to check the stick at the top of this subforum: viewtopic.php?f=4&t=123079

Second, you really need to understand that the Imperium is woefully under standardized even though they try really hard to maintain standardized patterns for all the most common gear. The lasguns, body armor, training standards, availability of transports, etc. in podunk PDF won't be the same as what Cadia is fielding and even Cadia won't bring the same toys to every fight.

Third, anybody arguing using a weapons magazine as a grenade as a massive feature is missing the plot. It's a neat trick, useful when you're out of supply and getting overrun, but it's nobody's first choice and probably doesn't come up in more than a small percentage of battles. Far more likely is that one side or the other is overrun before exhausting their supplies, or both sides settle into a long siege where using magazines as grenades means not having spare mags for your rifles. It's a niche usage at best and an actively poor feature at worst.

Fourth, the standard Space Marine tank is the Predator but you're likely to see more Razorbacks and Rhinos fielded in most engagements. Demolishers are designs that go back to the self-propelled guns of WWII and are more for anti-fortification work than anti-armor work so the fact that they could one shot a modern tank is less relevant than how quickly it can engage and fire on said modern tank. You should also focus more on Imperial Guard/Astra Militarum armor than Space Marine armor because Space Marine units win battles but guard companies win wars.

Fifth, you seem hung up on firepower. Packing more bang into a gun is pretty pointless if a 5.56 round still kills a person dead or forces him into carrying a back-breaking amount of armor in addition to his usual gear. The best feature of a lasgun is that it's dirt cheap, reliable, and ammo can be restocked even in situations where resupply is impossible. Those things mean way, way more than if they can explode a man's torso in a single shot.

Finally, your thoughts seem really scattered. Take a step back, figure out what specific questions you want to ask and then ask them clearly. I'm having trouble figuring out what information is actually important to you and what you want the info for based on your current posts.

[Lord Revan]

We should remember that the Imperium being understandardized is "not a bug but a feature" that serves 2 purposes first and more importantly (from the PoV of High Lords of Terra) having only vague standards within the imperium prevents troops from different planets from effectively joining up to rebel against Terra as their logistical organizations would be incompadable and secondly it allows the guns be used and built in a wide variaty of planets with very different technological levels.

That said SM are the most flexible imperial forces in their own niche, having (shock) Infantry ,AFVs , air support, artillery support and orbital support in a single unit more or less. IG has at most AFVs and Infantry or Artillery and Infantry or in very rare cases with specialized regiments Air Support and Infantry. normally Air Support and Orbital Support are the role of Imperial navy and as with everything in the imperium the way to use it is convoluted at the best case scenario. Again this is intentional so that IG regiments have to rely on each others to work properly and this rebellion at one regiment will have limited effect due to not having proper combinied arms capability (which the loyal regiments sent to deal with them would have).

[Zixinus]

FancyDarcy, I think you need to READ what we are writing to you because you seem to just asking questions after reading reddit. In fact, please stop asking us to evaluate reddit threads, unless you are asking us to make fun of them (this board does have a tradition doing that, although one that is dying out). Make your own arguments if you can, please. Or if not, quote the relevant sections for us. If we wanted to read and participate in reddit threads, we'd be on reddit.

To answer your overall question:
Minor or mayor technical features do not win wars. Rare, individual wonder weapons do not win wars. Quality and quantity of soldiers, trained and equipped well to fight the war you need to fight wins war. War is highly situational and complicated, there are entire volumes written about this topic.

It's like, you looked up the Israeli Galil but the only thing you noted about it that it has a bottle-opener. You are asking questions why and how important the bottle opener is rather why it is using the cartridge it fires and how does it handle it, how many rounds can it fire before expected failure or how accurate it is. These are the important things, not the bottle-opener (which, if you must know, was implemented along with wire-cutters to adept to non-combat needs of the soldiers deployed, which include opening bottles because a lot of soldiers are reservists who drank from soda-capped bottles and were abusing ammo magazine to do it lacking anything better on-hand).

Note: I'm typing this on a phone,
How useful is charging cells in a campfire?

Not much. It is better than nothing (which can mean a lot when you have close to nothing) but if you are at this point, you are already fucked as a Guardsman. From a more strategic perspective, it doesn't matter because if your soldiers have to do this then they are lost. Your guardsman are now this step away from either improvising weapons or trying to use the enemy's (which in WH40k, isn't always possible). They are not fighting units, they are straggling survivors that either manage to rejoin the main forces or get picked off.

It IS a neat trick but not again, this is not one that will battles for you or do much else. It is not important. The ability to reload your weapon from any electric socket is much, much more important.

What kind of fuel would you use to stay a fire out in the sandy desert?

Deserts are defined by their lack of vegetation, so the answer would be probably between "shit" and "shit all". In facts, your own shit might be the most dense fuel you have around, once it dried out. And any plan that relies on shit needs be discarded because that's what you do with shit.

The ability to be used as a melee weapon is actually claimed a lot on online debates.

Because people don't understand what is important in war*. They focus on what they find cool. Hell, sometimes soldiers ,and even officers, don't always understand what is important in war and lost wars because of that.

A few example questions: The ability to go from rest to ready to enter the fray in time. How fast you can get your tank from the garage to have it rolling. How long can your vehicles last on a single refuel. How much maintenance do they need and how reliable they are (WW2 Germans learned the hard way that having the best equipment is pointless if it spends most of its time broken or under repairs). How many things do your soldiers/vehicles need to function, how diverse and how much, everything from ammo to food to armor to spare parts for whatever. Because it matters a lot if you need a lot of one kind of thing or a few but bunch of different things, whether its ammo or batteries or whatever.

Some of these things WH40k Astartes and Guard do well, some not so much. The Imperium forces are better-thought out that a lot of sci-fi militaries but in the end, it's a fantasy military force (and saying that they're better thought-out is not saying that much). Maybe you should be asking people here what it is that the Imperium military does well and what it doesn't.

*Again, what is important depends on what war you are fighting. Remember, the WH40k Imperium regularly fights enemies that use melee-berserkers that forces its soldiers to fight melee. Plus also because chainswords are cool and look great on the figurines and artwork, thus they sell better.

[Lord Revan]

*Again, what is important depends on what war you are fighting. Remember, the WH40k Imperium regularly fights enemies that use melee-berserkers that forces its soldiers to fight melee.

more importantly some of those enemies can take sustained fire from man portable weapons and still get to melee range (like orks or traitor marines).

Also while quatity and quality matter in military forces, the intended role matters as well, You could have the best pilots in the world and a lot of them but it doesn't mean they'll be good at being riflemen it's not the intended role of a pilot.

What wins wars (or at least makes the enemy's victory too costly for them) is using your assets to the best of your abilities.

Lets use the Winter War as an example. On paper even if fully equipped the Finnish Defense Force was vastly inferior to the Red Army and finnish army was anything but fully equipped (in fact they have shortages with pretty everything).

However the finns used what assets they had to stretch what Moscow though to be 2 weeks operation with minimal losses into a slug fest that lasted for 3 and half months and costed the Soviets around 300 000 casualities in total from about 500 000 troops so while technically one could argue that soviets won in the end that victory cost them dearly.

[bilateralrope]

All you need to resupply lasgun-armed troops is a generator which would probably already be at any forward base, while autoguns require regular shipments of ammunition.

I have read sources that have them charging from Chimeras.

FancyDarcy, a Chimera is the guards basic troop transport. The guardsmen often won't even have to return to their forward base to recharge their lasguns as long as they still have fuel.

[Jub]

The guardsmen often won't even have to return to their forward base to recharge their lasguns as long as they still have fuel.

And in 40k pretty well anything is fuel. Wood, alcohol, corpses, if you can extract energy from it via combustion it'll get you some power even if the efficiency is awful.

[madd0ct0r]

I'm sure i remember lasgun magazine being solar chargable too

[Simon_Jester]

I actually wouldn't be surprised if he's seen sources indicating that a lasgun can do .50 BMG-level damage (that is, blowing apart limbs and penetrating light armor).

The big question is, do lasguns have better firepower than modern infantry rifles? Or has the Imperium adopted them for the good and simple reasons that they're more accurate and effectively impossible to run out of ammunition, even when resupply is nigh-impossible?

More the latter. Though it should be noted that 'autoguns', basically 40K versions of M-16s, do exist in-universe; lasguns are just more common, I suspect largely due to supply line concerns. All you need to resupply lasgun-armed troops is a generator which would probably already be at any forward base, while autoguns require regular shipments of ammunition.

I actually did think of pointing that out.

On 40k tabletop rules, lasguns and autoguns have (as I recall) more or less identical stats, which suggests that on the whole, neither is capable of doing vastly more damage to the body or penetrating armor significantly better than the other. I imagine the stats are more different in the RPGs and other supplementary material, of course.

This tends to support the proposition that the main advantage of lasguns is logistical (not included in tabletop stats), not firepower. And since autoguns are subject to the same ergonomic concerns as real life automatic rifles, they probably can't have much more firepower than, say, a real life battle rifle (such as the M14 as opposed to the M16)

Re Space Marines specifically: one-on-one, their weapons are probably more powerful (with some caveats) versus modern equivalents. Boltguns for example are basically automatic grenade launchers with variant munitions available. The primary difference is range; overall they are not depicted as fighting at ranges much over, say, 100 metres. Note that the flamethrower is a common weapon for them; these are hardly long-range weapons.

This is largely due to their mission profile of shock assault; they are not geared for long range battles of attrition. That's what the Guard is for. Marines are intended to get in close to the enemy and swiftly crush them. Their vehicles reflect this as well-- cybernetic walkers with close combat and close range weapons, close-air-support flyers, high-speed antigrav vehicles for strafing, light tanks that are basically converted APC's, and a very heavy APC.

If you want a closer equivalent to the modern military, you want to look at the Guard.

That said, even in real life, most infantry combat takes place at ranges of 100 meters or less, simply because the average human soldier isn't an especially effective marksman at any greater range. Longer range combat is dominated by what are for normal infantry support weapons, and the usual correct response when fired upon from several hundred meters is for everyone except maybe the squad machine gunners to cease fire and take cover while radioing for artillery support.

Space Marines, which are better protected against antipersonnel weapons and have less need to take cover at the price of spoiling their aim, and who just plain aim better than almost any human to begin with, would be more likely to perform well in such an engagement. However, the point that their tactics tend to focus on short range combat is still valid; the obvious reason for this is that when they fight enemy infantry, at long range they're mostly trading shots with the enemy's heavy weapons and artillery support, which are precisely the threats capable of taking out a space marine. In closer combat, the heavy weapons are less useful and the artillery can't normally engage them, increasing the advantage conferred by the space marines' armor.

Fifth, you seem hung up on firepower. Packing more bang into a gun is pretty pointless if a 5.56 round still kills a person dead or forces him into carrying a back-breaking amount of armor in addition to his usual gear. The best feature of a lasgun is that it's dirt cheap, reliable, and ammo can be restocked even in situations where resupply is impossible. Those things mean way, way more than if they can explode a man's torso in a single shot.

I agree with you, but it bears considering that the Guard fights a lot of things that aren't going to be stopped by a single 5.56mm rifle bullet, or even a fusillade of same. Having infantry rifles with significantly greater firepower might actually matter quite a bit to them.

On tabletop, at least, a squad of Guardsmen can put down a power-armored super-soldier by hosing him down with massed lasgun fire; they probably couldn't do that with small-caliber rifle bullets only.

[Jub]

I agree with you, but it bears considering that the Guard fights a lot of things that aren't going to be stopped by a single 5.56mm rifle bullet, or even a fusillade of same. Having infantry rifles with significantly greater firepower might actually matter quite a bit to them.

On tabletop, at least, a squad of Guardsmen can put down a power-armored super-soldier by hosing him down with massed lasgun fire; they probably couldn't do that with small-caliber rifle bullets only.

Yeah, in the context of 40k if you can get a little extra firepower here or there without hurting all your other advantages you'll take it. Hence things like scatter lasers, hotshot lasguns, lascannons, maybe even plasma guns to an extent?

The point was more that you rarely want more power than you need so don't fixate on it. If we had a more firm grasp on what it takes to put down common foes in 40k I'd have used that but IRL that power level is about what 5.56 round packs.

[Steelinghades]

On 40k tabletop rules, lasguns and autoguns have (as I recall) more or less identical stats, which suggests that on the whole, neither is capable of doing vastly more damage to the body or penetrating armor significantly better than the other. I imagine the stats are more different in the RPGs and other supplementary material, of course.

I believe a couple pieces of lore--Gaunts ghosts, I believe--seem to suggest that while the two weapons might be comparable in stats so to say, An autogun has greater difficulty piercing even guard Flak armour, whereas I'm not aware of a single source of that same armour stopping a lasgun--AFAIK, I haven't read all, 40k novels, but that seems to be true.

[Elheru Aran]

The thing with the Guard is it's all about the faceless horde of soldiers facing enemies which, in general, tend to be rather bigger than them, or even more numerous, or technologically more advanced... lore-wise, they rarely win against Necrons, for example. Setting off huge fuel-air explosives in underground caverns aside, which I suppose is where the extra firepower comes in.

Out of universe the reason 40K militaries (the Marines and Guard at least) tend to be a little better organized than the typical soft-SF military is because GW figured out long ago they could make so much more money by offering the entire range of military options. So that's why they have CAS and artillery, for example. One thing they do seem to lack is an option for calling in an equivalent to drone strikes. Perhaps servitors aren't smart enough to do the job, but I find that semi-unlikely.

I should note that while, yes, historically 40K has been pretty light on more advanced tactics like calling in air support or precision strikes, they do exist now and are part of the universe. So it's quite possible for a Space Marine to call in a tactical strike from overhead as they advance, for example, it just comes via Fire Hawk or whatever rather than a Predator drone.

On 40k tabletop rules, lasguns and autoguns have (as I recall) more or less identical stats, which suggests that on the whole, neither is capable of doing vastly more damage to the body or penetrating armor significantly better than the other. I imagine the stats are more different in the RPGs and other supplementary material, of course.

I believe a couple pieces of lore--Gaunts ghosts, I believe--seem to suggest that while the two weapons might be comparable in stats so to say, An autogun has greater difficulty piercing even guard Flak armour, whereas I'm not aware of a single source of that same armour stopping a lasgun--AFAIK, I haven't read all, 40k novels, but that seems to be true.

Regarding this: context matters. Cheap hive-built autoguns might not compare well to lasguns; high quality Mechanicus forge-produced autoguns could be equivalent. Game stats do treat the two similarly, but that's a balance issue. The assumption may be that the Guard would be more likely to be issued the nicer autoguns, while their opponents (unless traitor Guard themselves) would be less likely to have quality weapons.

The recent Necromunda game might be useful for comparison purposes, as autoguns are a distinct part of that game.

[Zixinus]

A small note: I recall from the wiki that lasguns are supposed to have power level settings, the max of which could penetrate weak spots on space marine armor. This is actually something that is tactically significant because it allows the user to increase firepower in a way that just using more guns won't.

It also has to be kept in mind that the Imperium technology is slowly declining in level and quality over the millennia. Hellguns are significantly more powerful but are rarer not just because of expenses but how much effort is required to keep them working. Plasma weapons are restricted and rare, something which the newcomer Tau don't have a problem with.

[Q99]

I actually wouldn't be surprised if he's seen sources indicating that a lasgun can do .50 BMG-level damage (that is, blowing apart limbs and penetrating light armor).

The big question is, do lasguns have better firepower than modern infantry rifles? Or has the Imperium adopted them for the good and simple reasons that they're more accurate and effectively impossible to run out of ammunition, even when resupply is nigh-impossible?

You can run out of ammo with them- ammo packs have a limit and you need a power source. That said, they're stupidly reliable, and the power packs can, in an emergency, be recharged by *throwing them into a fire*- which makes them unreliable, rapidly degrades them, and should be avoided but still.

As for whether they have better firepower, I feel the answer is solidly yes, how much depending on the model- some have highly variable settings (up to 'empty the clip in one shot' level), some don't (though usually still a little option). For use against Orks, you pretty much need more firepower than modern guns, because something like a M-16 simply doesn't have enough stopping power to stop an Ork charge without a lucky hit or a sizeable number of hits.

[Simon_Jester]

Well, sheer volume of fire from something like 5.56mm NATO would stop orks if you hosed them down with enough bullets; they're still made out of (approximately) meat (or something like it. However, yes, you do want heavier firepower for situations in which you may only get a chance to shoot a given ork once, rather than riddling them with a stream of bullets from a continuously firing machine gun.

[Lord Revan]

Well, sheer volume of fire from something like 5.56mm NATO would stop orks if you hosed them down with enough bullets; they're still made out of (approximately) meat (or something like it. However, yes, you do want heavier firepower for situations in which you may only get a chance to shoot a given ork once, rather than riddling them with a stream of bullets from a continuously firing machine gun.

Thing to remember also is that it takes a lot consentrated firepower to take down an ork (they're closer to a rhino or an elephant in terms of durability then that of a regular human). So the key isn't to just stop the ork but stop it before it rampage thru your lines.

[Simon_Jester]

Well, if you're in a position to hose down the target with machine gun fire, the range is presumably long enough that there's time for the cumulative tissue damage from ten or twenty 5.56mm NATO round hits to have an effect. Like, if you just dug in a massive gunline of guys with SAWs and had orks charge them across a wide open field, the barrage of machine gun fire would stop the orks just fine as long as there was a reasonable density of firepower.

It's when you're trying to dig them out of urban rubble that you'd want a gun with more stopping power.

Close combat is a horse of a different color, but I already mentioned that, see "you may only get a chance to shoot them once."

[Sea Skimmer]

Elephants would not be able to charge belt fed machine guns of almost any caliber. On the other hand sustained machine gun fire consumes ammunition tremendously, even in a positional world war one environment it was hard to keep the actual firing guns supplied. If you can't rely on 1-2 hits to even kill the target this is rapidly a problem. In that respect the Marines using bolters firing fairly large exploding rounds is probably
more efficient. Though in any visual depiction of Space Marines they also can't have more then ~30 rounds of ammo for the damn things either, which isn't any better then a modern grenadier with a 40mm launcher. Which suggests the whole swarming issue is actually oversold.

The huge advantage of machine guns is they can provide killing power over a very large dangerous space, out several hundred meters from the firing point. That makes it really hard to closely attack the machine gun equipped position, and grenade launchers can't really do the same thing, they provide a reaallly big beaten zone at the aiming point instead. But this is mainly relevant when a realistic enemy is crawling to attack you, not against a charge of monsters.

It wouldn't be hard at all to equip a modern force with suitable existing weapons to deal with the Ork swarms, we just aren't doing it right now because it would make no sense.