In 1854, Colt purchased a large number of U.S. Model 1822 flintlock muskets that the company altered to percussion cap ignition and rifled. The reworked muskets are dated 1854 on barrel tang and at rear of the lockplate. In most instances the original manufactory marks, such as Springfield or Harpers Ferry at rear of the lockplate, have been removed, while U.S. and eagle between hammer and bolster remain. Percussion nipple bolster is marked COLT'S PATENT. Some examples have been noted with date 1858. Barrel length 42"; caliber .69; lock and furniture burnished bright; walnut stock oil-finished.