There seems to be a rumor floating around the internet that George Soros is a major investor in Cerberus Group, which owns Remington, Marlin, Bushmaster and DPMS.
AS Snopes points out here, Cerberus is a closely held corporation.
That means the stock is not available on the market. The only way Georgy Gun Hater could invest in Cerberus is to be a founding member of the corporation, or to buy such a members shares.
Cerberus says he is not and has not. So you can relax. It is just another internet rumor.