The 9mm Flobert Bosquette, also known as the 9mm Flobert BB cap, is a rimfire cartridge that currently uses only a primer as a propellant, dispensing with the use of gunpowder.
History and design Designed in 1845 by Nicolas Flobert, it initially utilized a "double-aught" (00) buckshot pellet—weighing approximately 54 grains—as its projectile. Subsequently, as it was produced by various manufacturers, the bullet underwent modifications that also slightly altered the dimensions of the entire cartridge; whereas early versions had an overall length of 14.44 mm—with the cartridge case measuring 10.4 mm—current versions feature dimensions of 14.98 mm and 10.18 mm, respectively.
Currently, these rounds are used for "parlor shooting," small-game hunting, and pest control, as their low power makes them safe for indoor use; moreover, the absence of gunpowder results in reduced noise levels. Historically, the 9mm Flobert Bosquette has been produced by various companies—such as the UMC, Winchester Ammunition, Fiocchi, and Braun und Bloem, among others—and this cartridge also served as the basis for the development of the 9 mm Flobert Grenaille shotgun shell.
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