In the 1500s, spiral grooves cut into gun bores were used to spin-stabilize bullets fired through them. While the method of creating these grooves has changed, this system has remained the same and is considered “best” by nearly all barrel makers.
Attempts to improve land-and-groove rifling included choke boring, free boring, gain twist, deep and shallow grooves, few and many grooves, and odd and even numbers. No one system demonstrated significant superiority over another. About 1850, the first alternatives to land and groove (L&G) rifling made their appearance.
Charles Lancaster was considered the first to produce a rifled barrel using a spiral bore in England. Referred to as oval or elliptical boring, the oval interior was turned as though a straight oval tube was twisted, causing a bullet fired through it to be swaged into a slightly oval shape and spun as it traveled down the bore. The idea (in part) was to create a barrel that would perform equally well with a solid bullet or a charge of shot, but that goal did not succeed if experiments firing shot loads through rifled shotgun barrels are any indication. Nevertheless, the system worked with solid bullets. The success was tempered, for blackpowder fouling presented a more significant problem than a deep-groove rifled barrel.
The Civil War saw the Greene Oval Bore Rifle, an early bolt action wherein two bullets were loaded, with the second bullet with
