Tokurei Sochi Dantai Stella Jogakuin Koutouka C3 Bu

From MangaHelpers:
Yamato Yura arrives at her new high school dormitory and makes friends right away– her cute roommate Sonora, and Sonora’s friends Karira and Honoka. However, these girls all seem to have model air-guns, and, before Yura knows it, they’ve convinced her to join a club called C-cubed. Only after joining does she fully understand the meaning: Command, Control, and Communication. C-cubed is a club for people into survival games! Will little Yura really be able to handle herself among her new friends? [tethysdust]