Hollow-base bullet

A hollow-base bullet is an expanding bullet that has a pit or hollowed out shape in its base often intended to cause the bullet to expand upon firing a cartridge in order to expand the base against the barrel grooves and obturate the bullet more as it travels through the barrel. It is also used for improved aerodynamic stability and accuracy as hollow-base bullets are usually front-weighted which enhances their aerodynamic stability.

Two men have been credited of the invention of the hollow-base bullet: Captain Claude-Étienne Minié of the French Army and William Greener. The initial reason for developing a hollow-base bullet was to improve utility of muzzleloaded blackpowder rifles.

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