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View Full Version : Hypothetical Question: Silencers vs. EM gun supersonic crack?


AmesJainchill
November 19, 2008, 01:12 PM
Here's a question that's come up in one of my role-playing games. I could theorize all I want, but I'd like some input from people with experience with silencers.

Given an electromagnetic rifle or handgun, such as a railgun (http://en.wikipedia.org/wiki/Railgun) or a coilgun (http://en.wikipedia.org/wiki/Coilgun), where the only noise (from firing) is that of the projectile breaking the sound barrier, could it be silenced effectively?

I would suppose that a silencer would be somewhat effective on sound as it would be on gases. These are very small caliber weapons (3mm-4mm with larger calibers, 7mm or 10mm, for sniper rifles).

A special silencer design would probably be needed, I suppose?

Thanks in advance.

w_houle
November 19, 2008, 02:19 PM
If I am thinking correctly; the sound of a supersonic bullet will be heard after it passes you. You would not be able to tell the origin of the bullet from that noise alone, as it is a non- directional sound.

ZeSpectre
November 19, 2008, 02:33 PM
Since the round is creating a supersonic wavefront as it moves (continuing after it has left the barrel) it would be pretty much impossible to silence it.

Thus that sort of a weapon would probably be more effectively used as a one or two shot sniper gun, fired at a distance, where the projectile would hit the target long before the sound would reach it.

On the other hand, an EM or "railgun" could quite conceivably have a power dial on it where you could dial the projectile speed down to subsonic for close up/quiet work.

AmesJainchill
November 19, 2008, 04:33 PM
Thus that sort of a weapon would probably be more effectively used as a one or two shot sniper gun, fired at a distance, where the projectile would hit the target long before the sound would reach it.

If one was trying to be sneaky, that is.

On the other hand, an EM or "railgun" could quite conceivably have a power dial on it where you could dial the projectile speed down to subsonic for close up/quiet work.

Oh, they do. I was just wondering if it was possible. Which it's not, at least not at full power. Thanks!

scorpion_tyr
November 19, 2008, 05:37 PM
Railguns achieve their damage by the high velocity of the projectile. Dialing down the power to subsonic wouldn't make sense at all. You might as well throw the projectile. Throwing a suppressor on it would not work at all against the supersonic "crack". The only way to silence that would be to design a projectile that could achieve such high velocities without creating the sonic boom. Look into some of the research done by Skunkworks. Much of it will be classified but supposedly they've achieved similar results with supersonic aircraft. All of this of coarse is hypothetical. Even if railguns become a common weapon, I kinda like the smell of gunpowder in the morning.

ZeSpectre
November 19, 2008, 08:06 PM
Railguns achieve their damage by the high velocity of the projectile. Dialing down the power to subsonic wouldn't make sense at all. You might as well throw the projectile.

All firearms do their damage with mass and velocity. Doesn't mean a dialed down railgun would be less effective than a conventional pistol.

Heck I can see it now, future hunters bragging about how low they set the rail before taking their target.

Crosshair
November 20, 2008, 12:07 AM
All firearms do their damage with mass and velocity. Doesn't mean a dialed down railgun would be less effective than a conventional pistol.
The whole point of a railgun is to get insanely high velocities. If you are going to go subsonic you might as well use a firearm chambered for .510 Whisper and just put a big-ass suppressor on it.

To borrow a phrase from "Hunt for Red October". Having a railgun fire a projectile at subsonic velocity is like launching a SLBM sideways. You can do it, but why would you want to?

AmesJainchill
November 20, 2008, 01:04 PM
The description of the weapons points out, the primary disadvantage of EM guns is their high power consumption. You have to replace a C-cell (about the size of a pistol magazine) for every magazine of actual projectiles you fire from an EM gun. The subsonic option lets you cut that to one power cell for every 4 mags, but you cut your damage and range by half, which for a 4mm projectile is a big problem.

I assume the option for subsonic rounds is if you are low on power cells but not ammunition, or if you want to use a suppressor or just make less noise without a suppressor or just not waste the power on a shot that doesn't need it, say with the Sniper Railgun, 7mm, which does 6dx2 (roll 6 six-sided dice for damage, double the result) normally, but with a magazine of 30 shots you might want to just use the low power setting (half damage and range) for a relatively unarmored person within the lower range. You'd need the 12d6 high setting to disable vehicles or heavily armored soldiers or heavy equipment or whatever.

12d6 is overkill on anything but the heaviest armored people, really.