So I was at a gun show yesterday (the one at the Reliant Center in Houston), and I had a rather odd conversation with a guy who was running a booth full of ARs and related parts and peices. I was asking him about some model of free-float rail he had in the display - asking him whether it was one of the (few) that comes in two peices so you can install a free-float rail without removing the front sight base (like the Troy one). He launched into this diatribe about how that wouldn't be free-float anyways if I didn't remove the front sight base. The conversation went back and forth a bit as I tried to make sure we weren't misunderstanding each other. We weren't.
His contention is that if anything is touching the barrel, even a front sight base (or railed gas block, or whatever), that what you have is not a free floated barrel. I explained that I believed that all that matters was that the handguards aren't touching the barrel, so that pressure on the handguards (from your bipod, sling or hands) doesn't deflect the barrel. He said that wasn't really important, and that the point of being "free float" had to do with barrel harmonics, and as long as anything, even a gas block, was still attached to your barrel, these harmonics were still messed up and it wasn't really "free float".
I even mentioned that several major manufacturers sell complete rifles which they call "free float", all of which have a gas block of some kind on the barrel - I even mentioned that I didn't see how an AR could ever be "free float" by his definition, because you have to have something for the gas tube or you'll be manually cycling the action after every shot. At this point the debate was looking like it might get a bit heated, so I just said "whatever" and walked away.
So what's the deal here?
a) The guy's an idiot
b) The guy's right and I'm an idiot, and everyone that sells FF AR's is lying
c) The guy's smart but he was trying to see if he could manipulate my thinking in order to sell me some crap (which obviously stopped being a viable tactic once I started arguing back)
d) He's half right in some odd sense that doesn't really relate to the practical matters of the discussion?