When Melvin Johnson’s rifle design was first going through US military testing in 1938, it was set up to use box magazines. These magazines were a problem – they were not quite fully perfected, and were causing a lot of the problem that the rifle was having. Johnson opted to withdraw the rifle from trials, and revise the design to use a 10-round rotary magazine instead.
This took place after his relationship with the Marlin company had ended, and a machine shop called Taft-Peirce had signed a contract to make rifles for Johnson. They designated the new rotary magazine type of rifle the Model R, and made seven military pattern examples for further trials (as well as seven sporting pattern guns). the military model had a bayonet lug for a Krag/Springfield standard bayonet, and a wooden handguard on the exposed front section of the barrel.
Thanks to the Cody Firearms Museum for allowing me access to film this prototype rifle!