[3wbdriver]

I'm not aware of any difference between the rails. Picatinny as a Mil-spec standard. Some of the lights and lasers come with different inserts for different platforms. Is that possible with yours?

Of course it should be understood that there MAY be a little difference in the polymer rail on the Sub2K forearm. Try a little sanding here and a little sanding there until your Viridian fits.

 

[3wbdriver]

Ok. But a Picatinny mount is supposed to be able to fit both Weaver and Picatinny rails, while a Weaver mount may NOT fit some Picatinny rails. The wide of both rails is the same, but sometimes the depth and width of the cuts on Weaver rails is shallower. Is the clamp part of the Viridian just not opening wide enough? A picture of the light/laser would be helpful. And having said all that I'll be out of touch for the next 2 days and unable to help until later Monday.