Ok, but hear me out:

If you accelerate something into a freefall orbit, then it stands to reason that the projectile would deal falling damage (equal and opposite force, you know) which maxes out at 20 d6.

Applying real world logic to game rules never works out.

Also, you forget to take into account the weapon’s mass, form, structural integrity, the commoner’s reaction time, probability to fumble, the force of the wind, and probably a few dozen other factors that have an effect in the real world.

Just don’t. It’s a game.

I was just making a joke. Lighten up.

If a character has 121hp or more they’re able to jump from a space station onto earth with like a super hero landing??

theyd also need something to protect them from the friction and resulting heat of air brushing by at terminal velocity tho, i assume?

oh no wait, im making it too realistic

I want to play a game where there is an NPC roving band of guerrilla peasants that in times of crisis form a rail gun militia. Dragons? Rail gun. Tax Administrator? Rail gun. Cathy’s Baby Shower? Also believe it or not, rail gun.

Terminal velocity for a human is not fast enough to cause air to heat up. You’d probably get frostburn instead.

If you can manage to get someone into freefall I’d allow it. But no, equal opposite forces doesn’t mean you roll dice the same lol. Your sword does not take damage when you attack with it.

If you’re jumping from a space station then you’d be traveling at orbital velocity when hitting the atmosphere which is plenty fast enough to generate heat.

The obvious use of the peasant railgun is instant delivery. Gonna start my new enterprise, pFood, coming at you within 1 turn or your money back!

Unless the space station is not orbiting. Maybe it’s a mobile one like the Desthstar.

Fun fact about this in real life: A problem that gunmakers have had to deal with is that, although a faster-moving bullet fires straighter and penetrates better into its target, if the bullet moves too fast it will just poke a hole straight through a person without imparting enough of its kinetic energy onto them to be able to do real damage. So, i doubt the peasant railgun would be effective in real life.

In 5e yes. I think the theory is once you hit terminal velocity, you aren’t going to get any more damage from a longer fall.

Fun fact, I actually did have a villain do exactly that in a campaign once. The party achieved a secondary win condition during combat and so the BBEG jumped off the top of the space elevator to escape.

There’s a lot of factors, shape speed and deformation are all factors. Penetration and energy transfer are also at odds with each other in general. Gun manufacturers have this problem because speed is more or less capped by a practical barrel length, a rail gun can (theoretically) achieve enough speed that either factors start to become less relevant.

Pure theory, likely never ever going to be real, but could a bullet move so fast that it goes through someone without even damaging them?

… the death star orbits. The timer for the rebels to blow it up in a New Hope was how long its orbit would take to clear the moon in its path to the rebel base. The battle of endor was fought over the new death star in orbit over the moon.

Yes, the death star is capable of warp, but that just puts it into orbit over different things.

Cathy’s Baby Shower? Also believe it or not, rail gun.

Handing out gifts at the speed of sound.

That is simply not true. All you have to do is design your projectile in shape, construction and materials so the kinetic energy gets properly used to have the desired effect on the target.

A tiny 40 grain .204 Ruger bullet with the insane muzzle velocity of 4100 fps will absolutely explode a watermelon if you use a rapidly expanding projectile such as a ballistic tipped varmint round. If you use the same against a reactive steel target that was only rated for rimfire, it will melt a clean hole through it without even noticeably moving it. And if you use it against a bull moose, it will absolutely destroy a large amount of surface tissue but not achieve enough penetration to reach the internal organs for a clean kill.

It isn’t a simple problem, the are many different types of dynamics that you can encounter depending on the nature of the projectile, velocity and target.

No, but if it travels fast enough it would disintegrate and you could argue the resulting plasma blast would be what actually damages the target.

Relevant XKCD (in video form).