Pat Rogers did a comprehensive review of the LWRC guns in the March 2009 issue. He had two M6A1 guns & 1 M6A1 upper that he had students fire in classes over 10 months that involved 60k rounds fired through all three guns. He detailed what parts broke at what point.
Below is a link to the issue which is downloadable for a fee.
http://www.swatmag.com/content/issues/view/march_2009