With everything that you see in the picture above (including an all metal slidefire stock and 3x magnifier) it weighed in at 9.4lbs with no mag. Seems like alot but it is WAY better than the 11lbs when it was in a sparta. The rail will be streamlined, this was just to see if it worked....which it does!
I will weigh just the rail tonight to see what it comes too
I only have a 580 model. I will have to see if I can find someone local to check that with. It mounts to scope rings and barrel up front. I would say ejection shouldn't be a problem but again I got to try to find someone local with that model.