I need to know if a suppressor would fit under the Samson rail.

Also [dependent on this being 1.375 or better] if anyone has a 9inch SAMSON MRFS for sale [used] shoot me an IM.  

I have one of the first Samson MRFS-MX (10") models.  Someone asked me what the inside diameter was when I did the initial review, and looking back at that thread I measured the shortest inside diameter @ ~1.360-1.365" using a caliper.  Looks like you might need to go 1.25" diameter suppressor or smaller.

Thanks for the info.

I spoke to the owner of Samson and he mentioned that for additional cost they can open a  few inches of the rail system, but not the entire rail, so for that it's either turn my can or try something crazy with a drill press and a 1 3/8 HSS hole cut saw with a long bit extension.   I think turning is the best idea of those. I'm not sure I like the idea of reducing .060 wall to .050 wall thickness either.