[quote=@catchamber] Just stating my observations.[/quote]Confused you with FrostedCaramel for the moment so pardon me on that. [quote] Considering fusion's unrealistically powerful in this roleplay, we could provide lots of hydrogen from Earth, Mars, Ceres, asteroids, outer system planetoids, and comets. We could also provide lots of helium from Mercury, Luna, gas giants, and Kuiper belt objects. If we add in all the statites, orbital tethers, other reactionless drives, aluminium oxide fuel from Earth and Luna, and methane fuel from wherever organic people live, we end up with most spacecraft almost always having enough fuel for constant acceleration, deceleration, course corrections, and spin gravity.[/quote]Not even close. Just because you can replenish your fuel that doesn't mean you can freely waste it on full throttle. That and depending on fusion mechanism you can't even naturally replenish your reactor fuel. Similarly your propellant is cheap but not something you can ignore. But this is almost irrelevant. What isn't is that if such were plausible then it'd invalidate almost anything but laser weapons from combat because there's no way a projectile or even a missile could catch up to them. 200km/s is a nice average value which is fast enough to be "interesting" thus viable for cool space battles and feasible space travel yet it isn't too much to invalidate much of the nuances and fun of the hard sci-fi. [quote=@catchamber]If the rounds are torpedoes, preferably multistage rockets that have their own railguns, they can reach higher speeds without needing excessively long cannons.[/quote] And that's the torpedo. We talk about the "coilguns" or spinal guns here. I think you missed my list from the previous page. Torpedoes could have railgun or coilgun mechanism giving them an initial boost but that's not our topic. It's about a gun launching a guided projectile with only the bare minimum of maneuvering capability. Adding a propulsion unit to this would be counterintuitive. Not to mention the ship is unlikely to have enough energy to launch such a projectile. I think you could at least try to make a few basic calculations on this why. Even the pure KE required to accelerate a 20kg slug to 200km/s is 400GJ and with waste it would approach the terajoule range. If you try to get an at least 2-10 ton missile to reach the same velocity you'd need more energy than the first atomic bomb. That and again, these spinal guns fire relatively simple projectiles. They're far less sensitive to acceleration than a missile would. That being said there are still some inventive methods which might make this weapon a bit more interesting. I am just saying you have a bit of misconception here. [quote=@catchamber]Are you sure they're only hot because of magnetic acceleration, and not also due to the friction from hypersonic motion through air? Even if they're still scalding when launched through vacuum tubes, I'm sure you could find a way to exploit that heat to generate extra thrust.[/quote] Absolutely. Look, firearms push the projectile with the expansion of gases at extreme temperatures and hypersonic velocities. Do the copper and lead bullets melt in the process? No. During the operation of the railgun you focus the magnetic fields on the projectile for repulsive force. You directly use energy to move it and this has certain inefficiencies which shows in heat buildup. As for using that heat for extra thrust...it's plausible but you would lose much more in the possess. You'd have to add complexity which reduces the max acceleration the projectile can bear. You'd also need to add some kind of propellant because few hundred degrees won't provide enough radiation pressure for this to matter. Propellant which is a dead weight in the overall scheme of things. [quote=@catchamber] Normally, I'd agree, but [quote=@Keyguyperson] ... quantum entanglement can transmit data instantaneously from one side of the solar system to the other.[/quote] [/quote]Wow, I think [@Keyguyperson] might need to nerf that since the potential for abusing this is huge and besides I think he only wants this for convenient "real time convos" between the governments of faraway factions. As things are there's absolutely no reason why people wouldn't exploit this for interstellar conquest and to establish empires beyond the solar system. ... Or create super drones that can be controlled from any corner of the solar system. Equally problematic. I know neither of these are Keyguy's intentions so this is why I tell you.