Plainfield Machine Co. was incorporated in New Jersey February 20,
1951. The records do not indicate when the corporation ended, however,
state corporation fees were no longer paid after the 1974 tax year. The
company utilized a post office box in Dunellen, NJ for their corporate
records and carbine related business. Plainfield Machine was a machine
shop. They manufactured and contracted to manufacture for other
businesses. Carbines bearing the Plainfield Machine name did not begin
appearing until 1965.
War Baby Comes Home by Larry Ruth, pages 748-752 discusses
Plainfield Ordnance and their carbines. Ruth indicates the company
history is somewhat fuzzy, but Plainfield was the successor to
Millville Ordnance. The "Millville Ordnance" name was trademarked in
New Jersey in October 1960, at an address in Union, NJ. For further on
Millville Ordnance, refer to the web page devoted to their carbines.
Exactly who manufactured what, when, and where, versus
contracting with Plainfield Machine Co., has not been determined. What
is clear is carbines bearing the logo of Millville Ordnance (MOCO
within a banner) were the predecessors of carbines bearing the name
Plainfield Machine. Ruth's work on Plainfield Machine and their inner
workings is interesting, and includes an employee's insight into the
day to day operations and changes over time.
The earliest advertisement for a Plainfield Machine M1 carbine, found so far, appears in Shotgun News May 1, 1962.