I found this on a Russian Site.
http://ru.althistory.wikia.com/wiki/Remington_Model_53
Note the picture. A caption within the picture, in English, states that the only Mod. 53 ever made resides at the Remington Factory.
Neat looking gun. I would love to see how its operation differs from a Browning, et al.
Regards,
Gunny John