I'm not Japanese, I don't speak Japanese, and I have 0 idea what this video is about. My speculation is that it's taking the guns from an anime and talking of their real life counterparts.
Thank you for the comment(^^♪ It`s talking about what guns using in Jormungand`s characters which is Japanese TV anime series. This movie I explained that 4 of main member`s gun and the gun`s explanation briefly. And other one movie ② explained other character`s guns. but sorry there is no English sub titles...