Weird one, but here we go.


-A modern world, with the same laws of physics/same materials, weapons, etc.

-The player is a normal human. Think baseline average American citizen that has a normal physique.

-The player is able to use RPG-Leveling elements to level up.

-The player can increase his Endurance. Each point in Endurance extra is another 1% efficiency of the human body at preventing injury. (So, 1% better at stopping cuts, enduring heat, stopping blunt trauma, etc).

Question: How many points in Endurance would the player need to have before 9mm pistol rounds stop being lethal and turn into mere annoyances? (Where the skin/muscle can negate/stop the force of the bullet)

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    $\begingroup$ Rephrasing your question: "each month I get a salary raise of 1%. How long will it take before I can buy a Murcielago?" You are giving us no starting point, nor any description of the damage mechanism in your world. And once you give us those, it's just a math problem $\endgroup$
    – L.Dutch
    Commented Aug 31, 2022 at 7:53
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    $\begingroup$ Hard to tell, since body resistance is not quite linear ^^". Let's take aside "critical hits" like head, heart, lungs, big arteries and liver -yes, there are a lot of sweet spots-, if you shoot 240 times a 2J airsoft gun at the exact same point, the results won't be as devastating as shooting one 480J 9mm Beretta gun, 'cause only the latter would create a cavity and propagate the energy very deeply. $\endgroup$ Commented Aug 31, 2022 at 8:07
  • $\begingroup$ This question is answerable: you need to have an idea of how much force per square inch your skin can hold and only receive a bruise, then look at the bullet energy of a 9mm round. Each level takes 1% off that energy, so if at say 30% bullet energy it stops being lethal you'd need to be level 70 in endurance. $\endgroup$
    – Demigan
    Commented Aug 31, 2022 at 8:14
  • $\begingroup$ @Demigan The endurance increases resistance by 1%, it doesn't directly decrease energy by a fixed percentage (in which case 100 endurance means bullet invulnerability). Nice idea though :). $\endgroup$ Commented Aug 31, 2022 at 8:17
  • $\begingroup$ @Tortliena then it depends on the interpretation of what the resistance works on. In "normal" RPG systems the resistance % is how much damage you reduce it by, so yes 100% would make you immune. If it strengthens the body itself then you'd have to reverse-engineer it: start with the Newtons of damage that leaves only bruises, then add 1% to that until you surpass the Newtons of a 9mm. $\endgroup$
    – Demigan
    Commented Aug 31, 2022 at 8:37

2 Answers 2


Human skin has a toughness of about 20MPA. while steel has a toughness of about 400 MPA so you need to be around 20 times stronger, level 2000, to be as tough as steel and reliably able to negate bullets.

For ease of use, perhaps have each level be 100% more toughness, so at level 20 you can resist bullets. At lower levels you'll certainly be pretty resistant, but a pistol round could still nick an artery.

  • 1
    $\begingroup$ one can get lethal injuries without the skin being pierced. $\endgroup$
    – L.Dutch
    Commented Aug 31, 2022 at 8:56
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    $\begingroup$ People can survive gunshots, so if you are 20 times tougher you'll probably be tough enough to survive gunshot bruises. $\endgroup$
    – Nepene Nep
    Commented Aug 31, 2022 at 9:16

There is a good reason why many games use dice.

Depending on where exactly the 9mm round hits, effects on a normal human can range from instantly lethal to painful but not debilitating. For that matter, even a .22 or a single shotgun pellet can be lethal -- but that is less likely than for a 9mm, .357 or other large caliber. An ordinary 9mm round can penetrate several inches of wood.

Having the skin "bounce" bullets, like Superman, is difficult because it underestimates trauma under the skin. It may also not be as helpful as pain tolerance, fast clotting blood (but not too fast ...), and quick healing, which might all be subsumed under "endurance." But a bullet through the eye, into the brain, would still be lethal.

To pull numbers almost out of thin air, say a hit by a 9mm bullet has a 5% chance of being painful but not impairing activity ("only a crease"), a 5% chance of being a clean, easily healing wound ("only a flesh wound"), and a 90% chance of a significant effect. This "flesh wound" should be looked after, of course, but in the heat of battle the character might shrug it off for now.

So you might argue that the human baseline has a 10% resistance against 9mm. Bringing that to 100% would be a 9,000% increase. If you assume that the resistance is linear.

  • $\begingroup$ You dont need to consider fleshwounds or eye shots. The question asks for lethal shots through skin and muscle. $\endgroup$
    – Demigan
    Commented Aug 31, 2022 at 10:44
  • $\begingroup$ @Demigan, a flesh wound is a shot through skin and usually through muscle. It is not called a wound for nothing. $\endgroup$
    – o.m.
    Commented Aug 31, 2022 at 11:04
  • $\begingroup$ I was more focussing on the fleshwounds not being lethal, so focussing on shots where the skin and underlying vitals can survive and "shrug off" a bullet would be key. $\endgroup$
    – Demigan
    Commented Aug 31, 2022 at 11:43

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