The case AGAINST free floating rails
I was talking to a friend who should be knowledgable this kind of thing and we got on the subject of free floating vs. non-free floating rails when I mentioned I was thinking about getting a free floating rail for my Colt LE6920. Here's what he had to say:
"The Marines teach teenagers how to hit an 8" circle at 500 yards with iron sights using a well worn M16 with a 20" barrel and they do it without a free floating rail. If you are doing competition shooting where you are trying to put one round on top of the next at 500 yards with your hand wrapped through a sling so tight your fingers are turning purple then you might could make an argument for a free floating rail. But on a carbine, with a shorter stiffer barrel, a free floating rail is pointless".
OK, i said. "So it may not help, but if it dosen't hurt, and you've got the money, then why not"?
What he said next kind of surprized me because I had not read this anywhere before.
He said "Free floating means just what it says, free floating, as in the front of the rail is not attached to anything. Take a rifle with an aftermarket free floating rail, kneel on one knee, hold it out in front of you horizontally then bring the front of the free floating rail down on your knee like you were trying to break a large branch, there's a good chance it will break at the barrel nut.
Now repeat this experiment with a drop-in non-free floating rail that is supported by the front sight base. Unless you manage to warp the barrel, which would be pretty hard on a carbine, chances are your knee will give out before you damage anything.
Now the only reason I was looking for a rail to begin with was I wanted a QD Swivel socket and specially was looking for a rail with the socket made into the rail for a more slim-line sling attachment. I don't plan on attaching any optics to the rail.
His recommendation was the Troy Drop-in Battle Rail. It's a non-free float rail with a built in QD swivel socket (must have for me).
I had just about decided on a DD Omega 7 (not the Omega X) but after looking at the DD and the small little allen screws that hold the rail snug to the barrel nut, and thinking about the stress on those little screws if you were to do what my friend said, I'm now wondering if the Troy might be a better choice.