Howdy! Folks, FYI in the book A study of Colt Conversions by R. Bruce McDowell on page #153. it states: "U.S. Richards' frames are found in both three-screw & four-screw types and all but 130 new frames listed in the two Day Journal entries, are cut for shoulder stock" So to me that means of the meer 130 cut for shoulder stock there's even fewer with four-screw type frames. But I must say looking through the hole section on the 1860 Army Richards Conversions there were no pictures of a four-screw framed version........Wild Ben Raymond