Gauss Weapons - Silent and Deadly

[Supplement Four]

I'm spending a little time looking through several issues of Traveller's Digest (one of my favorite Traveller aids), and I spy some commentary on gauss weapons.

Namely, that they're silent. I never really considered that. How cool.

Evidently, gauss pistol has a separate battery pack, inserted from the left side of the weapon, that provides power for up to two magazines. (Unlike the gauss rifle magazines that have integral battery packs include in the mag.)

But, a silent weapon, huh? Just the wind and the phitt, phitt, phitt of the burst, and the target drops.

 

[jfetters]

It is one of the reasons I have always loved gauss weapons - they are silent and pack a decent punch for a hand-carried sidearm. If I am generating a character and they can be awarded a weapon, I usually choose that if I can get away with it (i.e., ref allowed).

 

[G. Kashkanun Anderson]

Well, sure, there's no explosion; but I presume that the bullets are "launched" at hypersonic speeds -- in which case, there should be a stream of loud pops or cracks as the bullets disrupt the airspace around them.

This has probably been discussed ad nauseum by Traveller grognards over the years (TML anyone?), but I suppose if you invented a low velocity gauss weapon, then it would be relatively silent ... at a cost of accuracy and impact power.

 

[BigBadRon]

Except that the bullets can be made with optimal streamlining, to minimise the air disruption and reduce the sound that is produced.

 

[Supplement Four]

Well, sure, there's no explosion; but I presume that the bullets are "launched" at hypersonic speeds --

Doesn't Book 4 specifically state how fast a gauss rifle slug zooms towards its target? Heck, hold on....

OK. Looked it up. Pg. 37 of Book 4. The 4 mm, 4 gram needle bullet accelerates to 1500 meters per second.

That's definitely faster than the speed of sound. What's the sound barrier, somewhere around 400 meters per second at sea level, if memory servers (300 and change, I think).

So...that begs the question...should the gauss rifle slug promote a mini-sonic boom?

 

[deniable]

Doesn't Book 4 specifically state how fast a gauss rifle slug zooms towards its target? Heck, hold on....

OK. Looked it up. Pg. 37 of Book 4. The 4 mm, 4 gram needle bullet accelerates to 1500 meters per second.

That's definitely faster than the speed of sound. What's the sound barrier, somewhere around 400 meters per second at sea level, if memory servers (300 and change, I think).

So...that begs the question...should the gauss rifle slug promote a mini-sonic boom?

We were taught 330m/s. Anything faster will cause some disturbance. 1500 m/s is ~4.5 times the speed of sound, so I doubt it's silent. The weapon could be, but the round will make a crack.

FF&S for TNE allowed silent gauss weapons, but the muzzle velocity had to be kept under 300 m/s. The trick became using a fat (20mm), slow (300 m/s) round that could almost do enough damage.

 

[Supplement Four]

We were taught 330m/s. Anything faster will cause some disturbance. 1500 m/s is ~4.5 times the speed of sound, so I doubt it's silent. The weapon could be, but the round will make a crack.

I actually think that's kinda cool, for dramatic purposes.

"You hear a strange sound. A BOOM! A crack! Like two pieces of wood slapping together and echoing in a open garage, or a mutated thunder crack with reverb. It doesn't sound like a gunshot, but it's almost as loud.."

"Wha...wha...what is it?"

"You look around the corner, and a man stands there, a strange looking rifle type weapon in his hands. On the ground lies a dead body, blood seeping from under him."

 

[RossWinn]

It is pretty obvious that the shell is hypersonic, and that a subsonic round will have very limited armor piercing capabilities and would need to be much larger mass to give similar inpact energy to the smaller hypersonic round.

 

[atpollard]

We were taught 330m/s. Anything faster will cause some disturbance. 1500 m/s is ~4.5 times the speed of sound, so I doubt it's silent. The weapon could be, but the round will make a crack.

From the military jets and space shuttles that grace the coast of Florida, I suspect that it would have multiple sonic booms.

 

[BlackBat242]

Except that the bullets can be made with optimal streamlining, to minimise the air disruption and reduce the sound that is produced.

Reduce, yes.

Eliminate... no chance.

Each round may sound more like like Indiana Jones doing his whip thing, not a normal bullet... but there will definitely be some sort of sound.

"Damn, Marge... that's some large bubblewrap that guy is popping in the hallway, isn't it"

 

[G. Kashkanun Anderson]

Doesn't Book 4 specifically state how fast a gauss rifle slug zooms towards its target? Heck, hold on....

OK. Looked it up. Pg. 37 of Book 4. The 4 mm, 4 gram needle bullet accelerates to 1500 meters per second.

That's definitely faster than the speed of sound. What's the sound barrier, somewhere around 400 meters per second at sea level, if memory servers (300 and change, I think).

Honorable mention should be given at this point to the VRF Gauss Gun, a few pages later in the book. Knocks out 4000 rounds per minute through a cryogenically-cooled barrel at 4500 meters per second. Now that's gonna wake the neighbors up!

Of course, no one's gonna pull that on you in a dark starport alley, either.

So...that begs the question...should the gauss rifle slug promote a mini-sonic boom?

The most useful ones will ... unless silence is an explicit part of the utility you're looking for.

I would guess that the silent versions will have a much more spurious reputation, and as a result should occupy a place further down along the law level charts of most worlds. Pistols are one thing; but I think you would seriously raise quite a few eyebrows if you walked into a gun shop and asked for the quietest rifle that they had in stock.

 

[Supplement Four]

So, a rifle that fires a bullet at four times the speed of sound. I've got a new respect for gauss weapons. The description sure lives up to the incredible CT stats, don't they.

A slug fired a Mach 4.

And...no recoil? Right?

 

[G. Kashkanun Anderson]

So, a rifle that fires a bullet at four times the speed of sound. I've got a new respect for gauss weapons. The description sure lives up to the incredible CT stats, don't they.

A slug fired a Mach 4.

The VRF essentially fires a stream of metal at Mach 13+. And assuming the crew can keep it from jamming, it can apparently keep this up for about seven and a half minutes straight before needing to reload.

I also wonder about the temperature of those bullets by the time they've reached their target.

And...no recoil? Right?

That's the common Traveller assumption. I have to imagine Newton's Third Law still applies to this situation, however. A gauss launching system might have an easier recoil than your typical "bang, bang" gunpowder round, since at least there's no explosions involved. It's got to be a more efficient conversion of energy, at least.

Although you'd think that at the tech levels involved for these weapons, some bright bulb would've had the idea to apply the P/FGMP's gravitic recoil dampening technology to all slug throwers, making them all essentially recoilless (while, admittedly, at a considerable additional cost). You could make a pretty mean TL-14 "rich man's" shotgun if that were the case.

In fact, I think the Mongoose Traveller's playtest documentation alludes to that as a plug-in option for high-tech guns.

 

[sablewyvern]

The VRF essentially fires a stream of metal at Mach 13+. And assuming the crew can keep it from jamming, it can apparently keep this up for about seven and a half minutes straight before needing to reload.

Given the muzzle velocity and assuming a 25-30mm long projectile, the upper theoretical end of the fire rate should in the vicinity of 50,000rpm, which is probably an achievable cyclic rate. Whether or not 50k offers significant benefits over 4k at those sorts of speeds is probably debatable.

It's worth noting that modern miniguns employed in anti-air roles generally fire at around 6,000rpm.

Edit: I note you list the muzzle velocity as Mach 13. I was woking on a Mach 4.5 (1,500m/s) round, so maximum theoretical cyclic rate would be vastly higher.

That's the common Traveller assumption. I have to imagine Newton's Third Law still applies to this situation, however. A gauss launching system might have an easier recoil than your typical "bang, bang" gunpowder round, since at least there's no explosions involved. It's got to be a more efficient conversion of energy, at least.

Recoil will be reduced by the lighter weight or the round, and increased by the high muzzle velocity. The important factor is that acceleration occurs along the length of the barrel, rather than all at once as with conventional chemical firearms. It's this last factor that will significantly reduce (but probably not completely eliminate) noticeable recoil.

Similar reductions in recoil can be achieved by using gel or liquid propellants that continue to be injected as a projectile travels down the barrel.

 

[Renaissance Man]

The important factor is that acceleration occurs along the length of the barrel, rather than all at once as with conventional chemical firearms. It's this last factor that will significantly reduce (but probably not completely eliminate) noticeable recoil.

Does that make a difference? You've still got a round (or stream of rounds) leaving the barrel at mach 4. I'd think that as far as the muscles and tendons in your arm are concerned, it will still FEEL like the force is happening all at once.

 

[sablewyvern]

I'm no physicisit, but apparently it does.

F=MA, and for any given muzzle velocity, the accelertion must be higher when it is all imparted virtually instantaneously.

Admitedly, there doesn't seem to be a lot of difference between applying that acceleration over the time it would take a guass projectile to travel the length of the barrel, and the explosive version, so I may have been misinformed.

 

[avi.hecht]

F=MA, and for any given muzzle velocity, the accelertion must be higher when it is all imparted virtually instantaneously.

The governing factor in the 'kick' your shoulder feels is Impulse
(I = Fdt = mdv)
In a conventional rifle most of the accleration occurs at the moment of explosion (some happens in the barrel as gasses expand) so most of the force is applied over a very short time - hence big kick.
In a gauss rifle acceleration is uniform over the barrel - so a lesser kick will be felt for the same bullet final velocity.

 

[jec10]

Appropo the first message of this thread, another excellent old resource is the Q&A in DGP's Megatraveller Journal. In MTJ No.2 page 55 Joe Fugate writes about the supersonic gauss bullets question: he recalls that he once sat next to a weapons designer on a flight to Chicago, and this designer told Fugate that it would be theoretically possible for a weapon to fire a supersonic bullet that made no noise. The key, according to Fugate's recollection, would be to design the projectile so it had a smooth flight, with no wobble or turbulence, and to get it up to full speed inside the barrel of the weapon.

 

[Border Reiver]

I remember that MT Journal piece and have use it in the defence of the silent gauss before (and been shot down in flames for it....:smirk. Now though I think that the (near) silent gauss weapon is entirely possible using correctly designed flechettes.

Both Lockheed and BAe have provided demonstrations of reduced sonic boom technology, I suspect by TL12 it will be a given and the silent gauss will be the weapon of choice.

 

[jfetters]

Regardless, I could see the application of a subsonic gauss weapon for sniper duty, where the target would likely be unarmored, or the part of the target's body was unarmored...