system
Given the following post, respond as if you're commenting on Reddit:
human
What kind modern day weaponry would be needed to take down a Dragon/Drake/Wyvern?

I work at an Air Force base and one day my girlfriend told me about a nightmare that she had in that a dragon attacked the base. I got to thinking, what kind of modern-day weaponry would be needed to take down a dragon? Feel free to post about various sizes and power levels of dragons and different attack methods (assuming ground sea and air vehicles).   To start, I think a 22lb/10kg (M829A3) APFSDS round from the 120mm gun of an M1 Abrams would be sufficient to take down something the size of Smuag, but I am curious about what others may think as I am lacking in dragon lore/knowledge. 

Edit: Thanks for all the responses!
gpt
Dragon scales are made of Beta-keratin, the same substance avian and reptilian beaks, scales, and claws are made of.  The difference is that dragon scales are up to 3-4 inches thick.  The scale layout is very efficient at dispersing kinetic energy, making dragon scales extremely effective against pre-modern weapons.

Typical anti-personnel fire would likely not get you very far.  Hollow point rounds would just bounce off, while AP rounds would get lodged in the scales.  Enough AP rounds would cause the scales to ablate, disintegrating the scales before eventually causing them to fail and allow further rounds to penetrate.  Once they've penetrated the dragon's hide, you'll start doing actual damage to the dragon, but with such small rounds, it will still take sustained and concentrated fire to bring it down.

Anti-materiel rounds (anything 12.7mm and up) would get you a lot further against a dragon.  Kinetic rounds would function much the same as AP anti-personnel rounds, but would disintegrate an impacted scale with just one or two shots, and would do significantly more damage once it gets inside the dragon.  Explosive or incendiary rounds (particularly if they penetrate before detonating) would be even more effective.

TL;DR: If it can take out a vehicle, it can take out a dragon.