Also known as: Whitworth bolt, hexagonal projectile.
| Class | Rifled-artillery projectile system (mechanical fit) |
|---|---|
| Designer | Sir Joseph Whitworth (1803-1887), Britain |
| Bore | Twisted hexagonal; 12-pounder = 2.75-inch caliber |
| Forms | Solid bolt and explosive shell |
| Reputation | Long range and accuracy; imported for Civil War use |
The hexagonal system
Sir Joseph Whitworth, among the foremost mechanical engineers of his era, applied his precision-manufacturing methods to ordnance. Rather than rely on an expanding sabot, the Whitworth system used a mechanical fit: the projectile's flat-sided body matched a twisted hexagonal bore, so the shot followed the rifling by shape alone.
The 12-pounder Whitworth had a 2.75-inch caliber, and both breech-loading and muzzle-loading Whitworth rifles reached the United States during the Civil War. Trials in England demonstrated extraordinary range and accuracy for the period, results that made the guns prized for long-range and counter-battery work.
Identification
Whitworth projectiles are unmistakable: a slim, flat-sided (hexagonal) body with a twist, made as solid bolts or as shells. Their mechanical-fit design and imported origin set them apart from the expanding-sabot and banded systems of American manufacture. Recovered examples are comparatively scarce and are prized by collectors.
On this site
Sources & further reading
- Melton, Jack W., Jr. Civil War Artillery Projectiles: The Half Shell Book. Blue Ridge, GA: Historical Publications LLC, 2018.
- United States Army, Ordnance Department. The Ordnance Manual for the Use of the Officers of the United States Army. 2nd ed. Philadelphia: J. B. Lippincott, 1862.
- United States Military Academy Ordnance Museum. A Descriptive Catalogue of the Collection.
- Hackley, Frank W. Civil War Explosive Ordnance. Revised November 10, 1960. U.S. Naval School, Explosive Ordnance Disposal.