By the way - perhaps some Doper here knows the physics and material properties - if a human body were literally 100x tougher, would it be bulletproof? What would be the impact of a bullet striking human flesh and bone in such a situation?
The Ultimate Tensile Strength of human skin is 27 MPa according to this study (see Conclusions). The UTS of steel starts of at around 400, up to high 2000s for some alloys. Kevlar is 3750 MPa.
Kevlar vests start at 4mm thick and will protect from pistol rounds, but not rifle rounds.
Your super skin at 2700 MPa and 2mm thick is probably not enough.
Probably? The issue is defining tougher - if we’re talking more dense, than average human flesh per most ballistic calculations is around 1.05g/cm^3 (barely over water). If we multiplied it by 100, we’d be looking at 105g/cm^3. For comparison, osmium, the most dense common element runs in around 22.5. So, yeah, probably.
If you used another metric, such as penetration ballistics, and instead just divided the penetration by 100, you’d end up with something much different. To avoid going into inhuman levels of links and comparisons, you can say that most handgun calibers run a penetration in ballistics gel (a human flesh analog) of 8" - 30" (caliber, bullet mass, powder, etc make a huge difference). This is based on the ‘heavy clothing’ assumption, so best unless you’re wearing body armor (which would be smart) or worse for you if you decided to run around in spandex (wrong on so many levels).
For what it’s worth the FBI recommend a round with 12-18" of penetration for stopping targets, and we’re leaving out a ton of other factors (barrel length, distance, etc). Okay, so with this we’re looking at a penetration of .08 of an inch (no worries unless it hits an unblinking eyeball) to .3 of an inch (dangerous to a lidded eyeball or close to the surface arteries). And this is without considering outliers such as handguns designed to fire traditional rifle rounds or ammunition designed for enhanced penetration.
So I’d call you bullet resistant, but not bullet proof - and if someone is using anti-vehicle rounds such as a 50 BMG, you’d still in for likely death.
Edit: for what it’s worth, I listed some penetrations based on handgun calibers, but with wrist breaking loads. I don’t think you’d see them commonly, but was just to give an idea of how wide a range you could be exposed too.