I can't mesure the weight of my guns, but I can get a rought estimate
Star G36KE Long barrel +silencer (to fit a 550mm inner)
I would say somewhere in the 9-10 pounds. All the weight is in the front, so it is quite hard to maneuver.
Worst I had so far was my ASP-2 T96 with the same 200mm silencer and a huge scope. Again all the weight is in the front. I would say it was close to 7-8lb.
Again it's nothing compared to RS... but still.