In the meantime in May 1854 the Board of Ordnance, not being entirely satisfied with the performance of the Pattern 1853 calibre .577-inch Enfield rifle, had engaged Joseph Whitworth, an eminent engineer, to try and improve it. Now Whitworth knew little about small arms or ordnance, so in 1855 conducted a series of experiments from which he deduced the twist of the rifling to be too slow for the length and weight of the bullet, causing it to become unstable at the longer ranges.

To prove his point he constructed a rifle of .451-inch calibre with a bore of hexagonal section with rounded angles, firing a bullet shaped to fit. At a contest in 1857 between Enfield and Whitworth rifles the latter won by a significant margin. So impressed were the commander in Chief and the Master General of the Ordnance that they both urged him to try his hand at ordnance. To assist him they supplied several solid 'brass' castings of ML guns up to 24-pr for boring and rifling with his hexagonal system.

Performances exceeded all expectations. For example, the range of a SBML 24-pr at 8° elevation was 2200 yards with the standard charge of 8lbs powder, while Whitworth's gun, firing a shot of the same weight at the same elevation, achieved a range of 3500 with only 2lbs. Indeed, so much did it exceed the anticipated range that the shot entered a house, narrowly missing a lady seated in her drawing room. What she said about Gunners I hesitate to record!