FYI, the Korean operating rod is manufactured by Shinsung Industrial Co. (Jeonbuk, Korea). It is made of SNCM439 alloy steel, similar to AISI-SAE 4340 steel. The steel was supplied by Gloria Material Technology Corporation (Hsin-Ying City, Taiwan).
The Korean operating rod was imported into the United States in early 2008 by Red, White and Blue, LLC (Springfield, VA). Operating rods imported by RWB were marked 7267064 and 18242. A RWB imported operating rod was tested for hardness on April 16, 2008 at Controlled Thermal Technology, Inc. (Phoenix, AZ). Hardness was checked at seven points along the entire length. The results varied from 42 to 44 HRC. Another sample was tested by Metals Engineering & Testing Laboratories (Phoenix, AZ) on April 28, 2008. The result obtained was 43 HRC. The current U. S. importer is Shinsung Industries Co. / Sierra Importers (Daly City, CA). The Shinsung Industries imported operating rods are only marked 7267064.
References: 1) Interview with Paul Sung, President, Shinsung Industries Co. (Daly City, CA) January 21, 2010 2) E-mail correspondence with Lou Biancospino, Owner, LRB of Long Island. January 28, 2010 3) approved ATF Form 6 to import M1A operating rod for Red, White and Blue, LLC 4) e-mail correspondence with RWB, LLC on various dates in 2007 and 2008 4) Controlled Thermal Technology, Inc. report dated April 16, 2008 5) METL report dated April 28, 2008.