Welcome to today’s Photo of the Day! Here we have an 1852 Colt Model 1849 Pocket revolver with factory “donut scroll” engraving attributed to Thomas J. Barlow, later fitted with a Thuer conversion cylinder. This combines early Colt factory engraving with the rare Thuer metallic cartridge conversion system. Thomas J. Barlow engraved for Colt from mid-1852 through 1854, creating distinctive circular scrollwork collectors call “donut scroll.” This revolver shows his characteristic style plus a bird on the left barrel flat, disgorging mask on the right, and patriotic shield on the trigger guard.
Alexander Thuer patented Colt’s first metallic cartridge conversion system used from 1869-1872. Only about 5,000 Thuer conversions were executed across all Colt models, with the Model 1849 Pocket being the rarest pocket model conversion. The system used tapered cartridges loaded from the front like paper cartridges, requiring a modified cylinder and removable breech plate with firing pin.
The Thuer cylinder is numbered 87048, from a different revolver. The base gun carries matching serial 29514 on loading lever, barrel, frame, trigger guard, and butt. Colt offered Thuer conversions to update percussion revolvers as metallic cartridges became standard. Customers could send guns back for conversion, or Colt converted unsold inventory. The system allowed switching between percussion and cartridge cylinders during the transition period.
Most of our POTDs utilize images from our friends at Rock Island Auction Company, the premier firearms auction in the United States. Take some time to browse their current auctions – who knows, maybe you’ll find a piece of history to take home!
“Cased Factory ‘Donut Scroll’ Engraved Colt Model 1849 Pocket Model Revolver with Thuer Conversion Cylinder.” Rock Island Auction, www.rockislandauction.com/detail/1049/3251/cased-donut-scroll-engraved-colt-model-1849-thuer-conversion. Accessed 6 Jan. 2026.
Writer | TheFirearmBlog
Writer | AllOutdoor.com Instagram | sfsgunsmith Old soul, certified gunsmith, published author, avid firearm history learner, and appreciator of old and unique guns.
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