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Home > Propellants, Firearms, and Ammunition Development > Ammunition > Projectiles > Cylindrical

By making the bullet cylindrical, a heavier projectile could be loaded into a smaller caliber musket. Cylindrical bullets fired from a smooth bore would start to tumble a short distance from the muzzle, losing accuracy and velocity at a rapid rate. This began to force the rifling issue because the effective range for aimed fire dropped to a few yards.

As military tactics moved away from the concept of massed fire to aimed fire by individual riflemen, tacticians had to consider ways to use rifled bores without the inconvenience of patched projectiles. Combinations of balls formed with high and low areas to exactly fit the rifling pattern were tested. However, they failed to find lasting favor with the military because they were difficult to load in a fouled barrel. Wooden driving shoes, called sabots, were fitted to round balls, but performance was inconsistent, loading was cumbersome, and they were prone to tipping. Another method that was tried involved loading an undersized ball that would fit past the rifling and any fouling buildup. The ball was then pounded with a ramrod against a surface or projection in the chamber to increase its diameter to fit the rifling. This required a very stout ramrod or mallet. In addition, significant danger was imposed upon the shooter and others due to the shock sensitivity of black powder. These methods were inconsistent and required significant modifications to the metal parts of the firearms.

cutaway digram of ammunition

Cut away of a
cylindrical projectile

The best solution proved to be a simple one. Col. Charles C. E. Minié combined the concepts of the cylindrical bullet and the undersized ball. He created a lead bullet with a cavity in the base that could easily slide down a fouled bore. When the powder charge fired, gas pressure expanded the skirt around the base cavity; this caused the bullet to increase in diameter, creating a tight fit in the rifling. Minié’s bullet increased accuracy, provided better gas sealing, and allowed rapid loading for volley fire.

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