A VERY RARE BRASS CAP PRIMER FOR A COLT PATERSON REVOLVER, NO. 233, CIRCA 1839-41 of standard production specifications, with folding lid, stamped with the number inside the body and with blued steel fittings throughout (the steel screw with light surface rust) 4.8cm; 1 7/8in diameter Colt's improved cap primer was included in his U. S. patent no. 1304 of 29th August 1839. For an illustration of the patent and a discussion of this see L. Wilson 1971, pp. 23-24.