Captain Patrick Ferguson patented his improved version of the La Chaumette breech-loading system in 1776. He employed the quick thread on the breech plug which enabled it to be opened by one turn only of the trigger-guard (already used by Bidet in London in the 1720's), but he improved the action to prevent jamming after a few rounds by cutting a smooth recess into the plug where it formed the breech end of the barrel, and a number of vertical grooves across the screw threads. The present rifle incoporates the first, but not the second improvement.
Ferguson demonstrated his rifle most successfully to the Board of Ordnance and to the King, whom he told that he could fire seven shots in a minute although "he would not undertake in that time to knock down above five of his Majesty's enemies". One hundred rifles were specially made (of which only one is known to survive), and a company of Riflemen trained to use them. They fought with distinction under Ferguson in the American War of Independence at the Battle of Brandywine Creek in 1777, but Ferguson was severely wounded and the project abandoned. He returned to the field in 1778 and was killed at the Battle of King's Mountain on October 7, 1780
Durs Egg, who made Ferguson's own rifles, produced some fine sporting rifles, the most distinguished of which, silver-mounted and gold-inlaid, bears the crest of the Prince of Wales and is hallmarked for 1782. It is preserved at Windsor Castle (No.L 420)