[1] The Whitworth rifle saw extensive use with the Confederate sharpshooters in the American Civil War, claiming the lives of several Union generals, including Major General John Sedgwick, one of the highest-ranking Union officers killed during the Civil War, shot on 9 May 1864, at Spotsylvania.

Whitworth believed that the same type of system could be used to create a more accurate rifle to replace the Pattern 1853 Enfield, which had shown some weaknesses during the recent Crimean War.

The Whitworth rifle outperformed the Enfield at a rate of about three to one in the trials, which tested the accuracy and range of both weapons.

The Whitworth Rifle Company was able to sell the weapon to the French army, and also to the Confederacy during the American Civil War.

Other long-range rifles of the period tended to have much larger and heavier barrels, which made them too heavy for standard infantry use.

[6][page needed] In 1860, the British National Rifle Association held its first annual meeting at Wimbledon.

Queen Victoria fired the first shot from a Whitworth rifle on a machine rest at 400 yards (370 m), and struck the bull's-eye 1 to 1+1⁄4 inches (25–32 mm) from its center.

On 19 September 1863, at the Battle of Chickamauga, an unnamed Confederate sharpshooter mortally wounded Union General William Lytle, who was leading a charge at the time.

[citation needed] Later in the war, on 9 May 1864, during the Battle of Spotsylvania Courthouse, according to popular accounts, Union General John Sedgwick was chiding some of his troops for lying down in a ditch to avoid Confederate sharpshooters at a range of around 800 to 1,000 yards (730–910 m).

Shots from Confederate Whitworth rifles, easily identifiable due to the shrill whistling noises their hexagonal bullets made in flight, caused members of his staff and nearby artillerymen to duck for cover.

The Whitworth rifle with a hexagonal bore and rapid regular twist, when it was tested by the Union's Ordnance Committee, along with the was admitted to have surpassed all the others for accuracy at long ranges.

The hexagonal-form bullet did not need to expand to properly grip the barrel, and therefore could be made out of a harder lead alloy.

While the telescopic sight was very advanced for its time, it had a reputation for leaving the user with a black eye due to the rifle's fairly substantial recoil.