Part of being an anime fan is resigning yourself to the fact that you're going to be watching a lot of high school kids. Even the stuff that is clearly aimed towards adults still ends up starring high school kids. Perhaps it's because anime is, at the end of the day, just cartoons and cartoons are for kids so if you enjoy cartoons then you're likely to enjoy other things that kids like. Like cheestrings and making forts.
So anime ends up creating these ridiculous schools that couldn't possibly exist. This is most often seen in ridiculously powerful student councils and other official bodies (cf. Medaka Box) but sometimes the school will branch out in other silly ways. This is where Tokurei Sochi Dantai Stella Jo-Gakuin Kootoo-ka Shiikyuubu or C3-Bu comes in.
C3-Bu is a show about a girls' school's airsoft club. You may have read enough at this point and be ready to go watch it. Go do that.
Specifically it's about them attempting to recruit and then train up a particular first year student who the club president has determined has the innate ability to be a perfect marksman. The little girl in question, of course, has never fired a gun in her life but enjoys the kookiness of it all.
As ever, there's a lot of moe-mess going on here, but there's also some fantastic send up of action as a genre. Their games tend to be themed so the battles will turn into an imaginary dreamscape where they're a real spy and damsel on a rescue mission or one of them really is Rambo laying waste to all the mooks she comes across.
If you love run and gun action, this is something for you to watch. If you enjoyed Girls und Panzer , this is something for you to watch.
Unfortunately, the better a show sounds the less likely you are to get hold of it. You may have noticed that the link I posted for C3-Bu was to a t-shirt imported from Japan and that's the nearest thing I could find to being able to get hold of this show in the UK (I think the US is actually in a similar situation for this one). It should be the easiest show in the world to pitch to people but maybe girls with guns gets an automatic snub from censors and buyers (I was about to link Upotte! but looks like Crunchyroll took it down). I didn't link Medaka Box earlier because the closest thing I could find to obtaining it in English, let alone in England was a poorly written self help book from Hong Kong which uses screenshots from the anime to teach leadership. Sucks to be us.
As for me, I've now seen it so I'm off to see what else is on.