POTD: Thompson .30-06 Autorifle Prototype – The Only One Ever Made
Welcome to today’s Photo of the Day! Here we have the only known example of an experimental Thompson .30-06 selective fire auto-rifle, documented in “Thompson: The American Legend” by Tracie Hill. Built in December 1943, this one-off prototype demonstrates how the Thompson submachine gun design could be modified for .30-06 rifle caliber.
The trigger housing appears to be a Colt/Auto-Ordnance component with original serial removed and “11” struck nearby. Electric pencil markings read “C.J. WEST JR.”, “Experimental”, and “12/43”, with “H.P. UNGER JR./CHICAGO, IL” stamped on the stock iron. Herman P. Unger Junior was a Chicago firearms dealer active after WWII whose career ended in 1972 after being caught with unregistered M2 carbine conversion kits.
The receiver measures 17 inches long – four inches longer than standard Thompson receivers. The two-piece magazine well accepts modified BAR magazines. Internally, the bolt resembles a Thompson bolt but uses brass flange levers instead of the Blish lock. The brass flanges suggest the designer was still attempting to apply John Blish’s theories about dissimilar metals producing greater friction under pressure – a theory that didn’t hold up in application.
The rifle weighs approximately 17 pounds unloaded and uses M1-style furniture with straight forearm, grooved pistol grip, and detachable buttstock. While John Thompson experimented with rifle-caliber weapons, no other known examples follow this format combining Thompson operation with .30-06 power.
The combination of flange assemblies creates significant friction when the bolt closes, but whether resistance was sufficient for safe operation remains uncertain. At 17 pounds, this steel beast represents an ambitious attempt to scale up Thompson’s design for full rifle power during WWII.
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!
“Prototype .30-06 Thompson, Class III/NFA C&R Machine Gun.” Rock Island Auction, www.rockislandauction.com/detail/4096/1356/prototype-3006-thompson-class-iiinfa-cr-machine-gun. Accessed 4 Mar. 2026.
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