I'm planning my first pistol upper build, with an 11.5" barrel.. What I'm thinking of doing, is running a EOTech xps, and a Streamlight tlr-2, both of which I already have. No plans for BUIS. I'm wondering if there is any way I can mount the tlr-2 on the top rail of a railed forend. With most railed forends I've seen, the rail sits at the same height as the rail on the upper receiver, which would be too high for the tlr2, as it would be blocking the view through the EOTech. I don't need a quad rail, ideally just something with a top rail, maybe a smooth free float tube with an add on top rail...but if the only way to accomplish this is with a quad rail then I'll pick one up.
I've considered a railed low-pro gas block, but I'd rather have it a little further back, plus I'm mildly concerned about heat issues.
For some reason, I seem to recall seeing a forend that had a "step-down" type of rail, where the rear section of the rail was at the same height as the receiver's rail, and the forward section was stepped down. Could be totally wrong on that though, might just be thinking of an ak type of rail.
Of course, if I can't find a suitable method for top mounting, I will just mount it underneath, and be happy with that.
Anyhow, if this post doesn't make sense, let me know and I'll MS paint what I'm talking about.