According to the cover note of the manga, Tennouji Kitsune
's manga Upotte!!
was announced to be getting an anime adaptation. The characters of the manga represent assault rifles such as M14, M16A4, SG550, G3A3.
PV of the manga
Manga Upotte!! had been serialized in Young Ace magazine since July 2009 and it has been transferred to Monthly Shonen Ace and 4Coma nano Ace magazines this year. 4Coma nano Ace are carrying four-frame edition of the manga titled "Upotte!! Nano".
Source: Scan of the cover note
Update Nov 26th
The official website of the TV anime: http://www.upotte.jp/