Military!

Episode 13 included with the Blu-ray/DVD release.

Kiss kiss, bang bang! The arms race takes on a startling new development when the arms come with heads, legs and very feminine bodies attached! Yes, at Seishou Academy every girl is literally a lethal weapon, and they're all gunning for the top shot at getting their own personal serviceman! Needless to say, it's going to be difficult for newly recruited human instructor Genkoku to adjust to working with a living arsenal of high caliber cuties with tricky names like FNC (Funko) M 16A4 (Ichiroku) L85A1 (Eru) and SG 550 (Shigu). Especially since many have hair triggers and there's no bulletproof vest that can stop a really determined coed! He'll have to rewrite the operator's manual on student/teacher relationships, and pray that his job description won't include having to field strip and reassemble one of his cadets in the dark. But unfortunately (for him) FNC's already thinking about becoming HIS personal weapon, and she usually gets what she aims for!

You may have heard of kung fu, but the girls at Oarai High School practice gun-fu—really, really BIG 75mm gun-fu, in fact. It's called Sensha-do, and it's the martial art of operating armored tanks! They take it seriously too, and since winning the national Sensha-do championship is such a huge deal at Oarai, they sometimes go to extreme ends in order to get the best students from Panzer class to sign up. Which is how Miho Nishizumi, who HATES operating tanks, gets drafted to join doomsday-driven driver Mako, even-triggered gunner Hana, highly receptive radio operator Saori and combustible tank-fangirl and loader Yukari as the incomparable Anko Team. They may not be on the half-track to fame and fortune, and maybe a few of them would rather shop for tank tops than become tops in tanks, but once their focus is locked and loaded, they're absolutely driven.

Makoto is determined to step out of her model sister's shadow and have her own high school debut, but when Makoto's sister shows up at her school unexpectedly things go awry.