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The Beretta M9, formally Pistol, Semiautomatic, 9mm, M9, is a 99mm Parabellum pistol of the United States military adopted in 1985. It is 8.5 inches in length. (via Wikipedia)
My fish tank
Desert eagle 2
Luger p08 pistol
Beretta m9 pistol
about an inch too big... but pretty much the right size