When he was in the real world, Casio obtained firsthand data through personal experimentation. Martial artists at the second level of accelerated blood flow could withstand the shots from small firearms when they put their all into a punch.
As for light machine guns, evasion is necessary.
If shot at the same time by a large quantity of machine gun bullets, even Casio would pay a severe price.
And as for stronger firepower heavy machine guns, sniper rifles ...
He would probably need to keep far away from them. The kinetic energy of these powerful firearms is no joke and is capable of penetrating his body.
"Martial artists, whose fists can penetrate armor as thick as knuckles, and whose swift hands can catch flying sparrows. Every time a blood node in the body is opened, the power doubles instantly when it bursts. Until the three nodes at the navel, heart, and brow are completely connected in a cycle."
