The Surefire M600 Scout Light is one of the most compact and lightweight rifle mounted weapon lights available. It is truly an excellent light. However, I have always had issues determining the best place to mount it since I do not care for tape switches and the standard mount places it in an uncomfortably low position for use with the support hand thumb. The Scout is a light in need of an offset mount but, until recently, no one made them.
Danger Close Consulting has filled that niche and filled it well! I have one of their mounts in hand and it is excellent.
Look for a more complete review with pictures to be posted here soon.