if she fires it while holding the gun like that she isn't going to sit down or pee for months

She's probably just the cute delivery girl.

Wrong. As we all know from several anime, that girl can fire that gun while running holding it up with just one hand and talk big at the same time... as she just again saves the day!

in japan, the laws of physics are just funny like that

Beyond that, that strip of bullets is quite tiny for such a weapon.

That many will be gone in about, oh, one pull on the trigger. Maybe two.

Fire rate is way too high for anything less than an ammo case at least her size feeding it.