Recoil on Gauss guns

[Zparkz]

BY FF&S1 standards the gauss weapons have comparable lower recoil than chemical propelled rounds at the same muzzle energy.
Would it be possible to lower the recoil further by increasing the length of the barrel by prollonging the time it takes to accelerate the projectile to the desired velocity?

The length of the barrel in FF&S is based on the muzzle velocity of the projectile.

Any ideas how to calculate this?

 

[kurtis]

Why does Gauss Rifle = no recoil?

 

[TheDS]

Well, without having to read that whole, 5 page thread, let me see what I can do to illuminate the subject.

IIRC, in Megatraveller, gauss guns were listed as having no recoil and no report. It was probably assumed that since it was just magnetic fields throwing things around, that they didn't matter, or they could be used as some sort of auto-compensation in some way.

Whatever.

FFS, however, doesn't take that tack at all. If you take the time to develop a CPR gun, and then to develop what you feel to be an equivalent gauss gun, you will find that the gauss weapon has MORE kick to it than a CPR gun. Once you factor things down so that the damage is equal, THEN you'll see that they're about the same, as far as the Recoil stat is concerned.

Now, why the comfusion of my last statement?

When designing a pair of guns, you naturally want to give them as many of the same stats as possible. However, for a gauss gun, you have to choose a muzzle velocity, whereas one is assumed for the CPR gun, so you don't know what to pick, and so you end up picking the wrong one. The gun comes out a lot more powerful than you thought, weighs a lot more than you thought (thanks to the battery), and has a lot more kick.

So you have to know how fast a bullet is supposed to travel before you design your gauss gun, or you should otherwise choose an equal muzzle energy, which requires a bit of math to figure out.

At any rate, tools at your disposal for reducing recoil are in the book. Gyroscopic compensation, gravitic compensation, even muzzle brakes and automatic fire and shock absorbing stocks (iirc). Even beefing up the weapon by adding otherwise useless weight helps.

But the most direct answer to your question about lengthening the barrel to reduce recoil goes something like this: a barrel that is twice as long should allow the bullet to accelerate at half the rate, and therefore give half the recoil. Naturally, you'll have to factor in the extra weight of the longer barrel.

BUT, why go through all that trouble? After all, if you have a longer barrel, that means you can get the bullets going twice as fast, doing more damage.

(Note that FFS assumes bullets will accelerate at a constant rate, whereas in reality, they do the bulk of their accelerating at the start of the trip, and each successive piece of the barrel imparts less and less of the total speed. BUT, don't let that distract you, there are so many deviations from reality in FFS that it's unusable if you want something realistic, but it's still perfectly fine if you want a consistent, simple (relatively speaking; compare with Gurps Vehicles 3e) way to make things that are compatible with the game. If reality os all you will accept, however, you're in for a LOT of work; trust me on this.)

 

[Zparkz]

A friend of mine (which happens to be an engineer) took up the challenge and found that the force felt by the person firing the gun wouldn't change much because it wouldn't matter much if the bullet used 1/1000th of a second or 2/1000th of a second to accelerate to the desired muzzle velocity. The total force will be the same and the body would probably not feel the difference between those two scenarios. And if the rate of acceleration is reduced to 50% the barrel length needs to be 4 times as long.

However there might be other effects that may come in handy, like better precision over longer ranges as the aiming will be more accurate. The increased weight of the barrel may reduce the recoil.

 

[veltyen]

It is all about efficiency and energy.

How about a true floating barrel that has freedom of movement from the grip. If you have two systems, one controlling the movement of the barrel, and the other projecting the projectile you can quickly end up with an artillery carriage arrangement. It still doesn't discount momentum though, as even with "perfect" energy recovery there will still be pressure from the weapon, though if the systems are good enough it won't resemble recoil from a modern rifle. You also end up with an insanely complex weapon you don't want grunts maintaining.

From an energy recovery point of view the moving carriage should be spinning a flywheel on firing the weapon. In a gauss weapon that could be upgraded to a compulsator (an electric device that uses a spinning wheel to generate extreme electrical voltages and current) that the batteries normally feed.

About the only solution is writing it all off as "magic". The easiest magic available is grav. Using a fast reacting grav based drive system that counters the firing of the weapon. The momentum still exists, however it is disappated into the local gravity in much the same way a large gun attached to the earth disapates momentum into the planet.

Which brings up a question. Do gauss weapons in 2300/2320 have recoil? With no grav the above trick won't be available.

 

[epicenter00]

Originally posted by veltyen:
Which brings up a question. Do gauss weapons in 2300/2320 have recoil? With no grav the above trick won't be available.

From evidence in 2300, I would say they certainly do. Otherwise, there would be no reason for the FAM-90 to have a lower velocity area fire mode.

 

[Antony]

I don't know why, but this made me think of a scene of a Kentuckian with one of those really long guns. This time something like a gauss musket in size.