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The following came up on my mind in the context of the only war RPG but might also be something I might include in further fluff stories:

Could anyone share a background related or physics based guess on how loud infantry lasweapons (pistol, gun, longlas) are? Are we talking something like the corresponding projectile weapons?

And relating to that: where would a possible sound come from? With projectile weapons we have the the expanding propellent gases as source (near the muzzle, therefore silencers) and I think the "shockwave" (and potential hypersonic boom) of the projectile in flight traveling with it. + relatively marginal compared to that the sound of the moving parts of the gun itself.
I currently don't see a real reason why a sound would be generated at the muzzle of a lasweapon. Would a potential lasweapon generate sound from the laserlight expanding air around it while it travels towards it's target?

Have there been mentions of Silencers for Lasweapons in the background? Are the Longlas weapons used by Ratlings and Assassins and the like silent?

A sufficiently powerful laser(to punch thru armour) would cause any moisture in the air to boil(surrounding beam) so there would be some sort of Soundwave produced.

I was thinking about this recently, when a lot of people were streaming Darktide last weekend during the beta period. There's a variety of las type weapons in that game, if you want to look up clips and hear some interpretations (some of which sounded off to me, and too similar to typical projectile weapons).

Based on the first few seconds of this, WH40K Lasweapons are not silent, but don't seem to be particularly loud either.

 Pyroalchi wrote:
Have there been mentions of Silencers for Lasweapons in the background? Are the Longlas weapons used by Ratlings and Assassins and the like silent?

The FFG games have a lasgun modification for reduced sound, though the main difference is to high the flash of the weapon.

 alextroy wrote:

Spoiler:

https://players.brightcove.net/5778310444001/I9LFnIlKSk_default/index.html?videoId=6157970120001

Based on the first few seconds of this, WH40K Lasweapons are not silent, but don't seem to be particularly loud either.

I was just about to link this. But yeah, you can get a sample of what lasguns sound like in various video games. I'll also link this: https://www.youtube.com/watch?v=CF8ex1Fgj0Q

It seems likely that "lasgun" is a catch-all term for a lot of similar-but-different weapons. Thus why some of them seem to have recoil and some of them don't. Some of them seem to be shooting actual lasers, while others seem to be shooting more of an "energy bolt". So the exact sounds they make are likely to vary from style to style. From what I recall, novels usually describe the sound of lasguns and laspistols as a "crack". The video alextroy linked seems to be a sort of "cha-choo" laser tag toy sound with two distinctive parts. It's hard to make out the exact shape of their projectiles, but it looks to me like they're firing brief bolts rather than sustained beams. So if I were to go out on a limb, I might take that to mean that "energy bolt" lasguns creating a three-part noise:
* The crackle of air/moisture being superheated within the weapon.
* The longer, softer crackle of the energy bolt in flight.
* Presumably a third, more-distinctive noise as the energy bolt hits something and transfers that heat energy into whatever it hits (potentially resulting in some kinetic force if the heat transfer causes the material struck to "pop" or evaporate or otherwise change its state in a way that results in some audible kinetic movement.)

Presumably, you could soundproof the chamber where the initial crackle occurs to reduce noise there. You could maybe do something to the firing chamber or barrel to catch/absorb some of the ambient light (preventing so much light from escaping out the barrel as a visible flash). Doubt there's much to be done about the sound of the bolt striking its target though. Maybe a lasgun with a more sustained laser-like behavior would be a bit harder to detect? Not in the sense that it's actually quieter (the beam would presumably still be causing the air to sizzle; even moreso than the energy bolt version), but in the sense that a steady sizzling noise might get interpreted by human brains as some sort of background noise.

"Ssssssssszzzzzzzzzzzzzzzzzzzzz" could conceivably be a weird wind or bug noise.
"Chachoo-chachoo-chachoo" probably isn't.

IRL "silencers" don't eliminate the sound. It just makes it more difficult to locate its location. When you see in movies the protagonist and antagonist trading silenced shots amongst an oblivious crowd; that is fake. The crowd would hear the gunshots. Suppressors (what most people call silencers) reduce/suppress the sound of the bang, but not eliminate.

Suppressors(not the primaris) reduce the velocity of the gasses as the escape the muzzle on a firearm. The quietest Suppressor I've heard is approx what a really loud human clap sounds like. The sound doesn't have enuff energy to sustain and it dissipates quickly.

If we are to believe lasguns work the way they "ostensibly" work, I can't believe a silencer would do anything

Longlas weapons do often have flash suppressors, most obvious in the Cadian command squad long las or the SM scout snipers. I think these just make it harder to spot where the sniper is firing from.

If the "crack" of a lasgun firing comes from vapourising water in the air along the bolt (as mentioned above), I doubt it will be very loud in most places. If that mechnism is accurate, presumably lasguns are quieter in deserts and louder in humid climates. Perhaps the flash suppressors also include dehumidifiers to reduce the noise at the barrel tip at least.

At the very least, the Kill team rules support that a longlas is less obvious than a lasgun when used, but that may reflect the training of marksmen.

Ratlings typically use needle rifles rather than longlas rifles, and these are supposed to be much quieter. The needle must be fired subsonic or something along those lines.

Tygre wrote:
IRL "silencers" don't eliminate the sound. It just makes it more difficult to locate its location. When you see in movies the protagonist and antagonist trading silenced shots amongst an oblivious crowd; that is fake. The crowd would hear the gunshots. Suppressors (what most people call silencers) reduce/suppress the sound of the bang, but not eliminate.

There are the Welrod pistol and De Lisle carbine, which are about as close as you can get to silent for lethal firearms. They are very niche and the suppressors have very short lifespans before they stop being effective.

IRL lasers do not make a sound. But that wouldn't do for Hollywood, you see.. which is why its a sound of a long bridge cable being struck, recorded on a Nagra IV and post processed.

I find it a lil hilarious to try to reason why a lasgun would make a sound.. especially why it would make a sound of a bridge cable being struck.. And how you could make that sound less.. AND WE DONT EVEN KNOW HOW TO REALISTICALLY CREATE A PRACTICAL LASGUN.

Another equally mindbending thought experiment would be to try to reason how to hide a muzzle flash of an energy weapon.. I mean, that light emanating from the muzzle is YOUR ACTUAL PROJECTILE Maybe you dont want to be shooting light in the first place if it being visible is a problem..

TL;DR - trying to portray energy weapons as having the same problems/solutions as projectile based weapons breaks "muh immersion"

Regarding visibility: the interesting question might be wavelength. Depending on what you want to explode lasguns might well operate in the infrared or Ultraviolett range

 tauist wrote:
IRL lasers do not make a sound. But that wouldn't do for Hollywood, you see.. which is why its a sound of a long bridge cable being struck, recorded on a Nagra IV and post processed.

I find it a lil hilarious to try to reason why a lasgun would make a sound.. especially why it would make a sound of a bridge cable being struck.. And how you could make that sound less.. AND WE DONT EVEN KNOW HOW TO REALISTICALLY CREATE A PRACTICAL LASGUN.

Light and other EM radiation doesn't make a noise, but the equipment generating it does. It also hit things on its path, which will then get heated and make a noise.

Modern pulsed lasers (which have a higher maximum energy than continous lasers and more closely match how lasguns are described with discrete shots) do typically make cracking or popping noises when generating the pulse. A very high-energy beam may also have noisy effects on the things it hits in the air on the way to its target, but I am not confident tht this would be auudible or significant.

Another equally mindbending thought experiment would be to try to reason how to hide a muzzle flash of an energy weapon.. I mean, that light emanating from the muzzle is YOUR ACTUAL PROJECTILE Maybe you dont want to be shooting light in the first place if it being visible is a problem..

TL;DR - trying to portray energy weapons as having the same problems/solutions as projectile based weapons breaks "muh immersion"

Lasers are normally only visible at the target- you cannot see the beam. Some light is scattered in the air, especially in smoke which makes the beams of weak lasers visible. A sufficiently strong laser may have a visible beam in air. A laser fired in vacuum is invisible unless you are the target. Obviousy if the target is hit in the eye it doesn't really matter if they saw the shot in their last moment...

I don't know if real-world lasers have an increased scattering of light where the beam transitions from the medium within the equipment and lense to air (I suspect they do with effects like diffraction), but this would be one possible mechanism creating a "flash" that could give away the position of a sniper without weapon modifications.

Now I think about it, I’m sure in the Cain novels, Lasgun fire is described as a crackle.

I also thought about the Ghost novels and I can't remember the sound of there Long-Las ever be a specific problem.

The various novels have always said they have a distinctive "crack". I always thought it is something like a whip being snapped. Not booming and loud like a firearm, but still very audible.

There are silencers in the various RPGs for Lasguns, though how they would work IDK. Maybe they convert the normally visible spectrum of light the lasgun emits to an ultraviolet frequency which can't be seen with normal vision. Of course, suppressors aren't actually used for stealth purposes IRL. Their actual purpose is to protect the hearing of the user, with some side effects of reduced muzzle flash that can kinda help prevent you from being immediately seen.

A lasgun would still have "muzzle flash" like normal guns, you'd always have some light scatter away from the beam and make it visible from downrange. So a suppressor to cover that up or convert the wavelength to an invisible spectrum would be useful. As well as noise reduction depending on how loud the sound of the lasgun actually is.

 Haighus wrote:

Light and other EM radiation doesn't make a noise, but the equipment generating it does. It also hit things on its path, which will then get heated and make a noise.

If we try to treat lasguns "realistically" this is likely where any sound comes from. I doubt superheating the air as the beam travels would cause too much noise, and it would dissipate quickly, but the process of creating the las shot might be quite noisy. Most depictions of las weapons have them producing very visible "bolts", which would seem to make the idea of silencing them pretty pointless as the main role of silencers isn't to make gunshots actually silent, but make detecting their location much more difficult.

I'd imagine a las weapon designed for stealth would likely be modified to use non-visible light wavelengths, with the sound being much less of a problem. That's functionally fairly similar to modifying current firearms to make them stealthier, through the use of suppressors and sub-sonic ammunition.

For those who have played the Dark Tide beta (or find a clip online) they seem to have nailed the sound to my mind. It sounds similar to how Abnett describes it. It's definitely less of a racket than an autogun firing.


We know that the Longlas uses a hotshot powerpack and has a longer barrel. That essentially leads to greater accuracy and less of a damage drop off at range. Do hotshots make more of a noise? It's a greater power output so that is a possible outcome. Based again on Abnett, the longlas requires frequent barrel maintenance due to the heat stress of the weapon. Presumably, this is why Stormtrooper lasguns have a much more distinctive barrel.

My personal assumption is that the device isn't really a silencer but something like a muzzle shroud which would help in obfuscating he light emission from the initial trigger firing. It might even serve as a focuser for the laser.

Thanks for the great input everybody. For our Only War Campaign I have set the assumption to projectile weapons being louder, but less visible and Lasweapons quiter but more visible together with the existence of "suppressors" shifting to invisible (without special equipment) wavelengths and reducing scatter.

Just because we have to work with something and that sounds kind of fair

The idea that anything can make las weapons more accurate amuses me

If anything, you want a big bulky automated focussing array that can keep the beam on target regardless of user ability

 Haighus wrote:
Ratlings typically use needle rifles rather than longlas rifles, and these are supposed to be much quieter. The needle must be fired subsonic or something along those lines.

Technically needlers are also lasers, they first fire laser making hole in armour then a needle delivering toxic payload through said hole.

 Haighus wrote:
There are the Welrod pistol and De Lisle carbine, which are about as close as you can get to silent for lethal firearms. They are very niche and the suppressors have very short lifespans before they stop being effective.

For conventional guns, maybe. Russians invented ammunition with built in silencer making guns using it (PSS pistol or OTs-38 Stechkin revolver) completely noiseless unless you count the sound of gun being reloaded

 tauist wrote:
IRL lasers do not make a sound

Completely wrong. Never mind sound of atmospheric backlash or generator working Haighus mentioned, the most practical lasers (and closest to lasguns) we made work on chemical laser principle - think bullets, except energy of explosion powers laser instead of propelling projectile. This is the best and lightest way of packing huge amounts of energy needed to fire it we have. If that particular lasgun energy pack works on chemical storage too, it might very well make loud sound every time lasgun is fired. Even if not, circuits tends to whine when huge amounts of energy flow through them (see videos of power plant substation for one example) - that might make good amount of noise too.