Isn't SVD a too big for a thin, little teenage girl?
Even if she is a trained sniper, she will face some problems, running around with it.
I mean, this rifle is not so heavy, but it's LONG.

I know nothing about guns, but in episode 10 it's depicted as being a little shorter than her. She carries it strapped on her back. I don't know how difficult it would be, but they do make it look easy...

Anyway, compared to some of the other technical issues I saw in this anime, this one's hardly worth mentioning...