On 14 January, 2010 RDMI (Robinsom Arms) filed suit in US District Court for Utah against Remington, Bushmaster, Rock River Arms, and Magpul Industries based on alleged infringement of their patent.
Below is the actual suit taken from court records.
Robinson Arms Lawsuit Alleging Patent Infringement
This is the third patent related suit filed against Magpul this year. The initial suit came from A.R.M.S. over their dual aperture rear sight followed by Vltor in October alleging violation of their patent on the Modular Firearm Buttstock.
Reading through the filing I find one thing a bit odd. It claims that the ACR has been offered for sale, which still has not happened, particularly in the state of Utah. Based on this it seems to me that the case was brought a bit prematurely and was staged to have the most dramatic effect during SHOT Show unless it was intended to delay the release of the ACR into the market. But then why include RRA?