I'm trying to figure out how one would go about mounting flip up sights on top of a free float tube. I know that a full length rail system is probably the easiest way to go, but idealy, I'd want a fiberglass or carbon fiber tube (I like the look better and black metal seems to heat up pretty fast in the Las Vegas sun). The more I look into this, the more I see people advising against mounting rails to a normal carbon fiber FF tube (such as a Hiperform, Clark, or Briley) and then putting flip ups on top because the screws can come loose over time and throw off your zero. Does anybody have any experience with this?
Also, what about the PRI Gen III tubes since they come with the rails mounted from the factory? Are they any better or is a full length rail system the only way to go?

Use threadlocker on the screws. I have seen Troy flip sights on the little rail on the frnt top of the PRI tube.

Or you could buy a full length aluminum rail and put a VFG and rail panels on it. Heat wouldn't be a problem then.

That's a good idea with the Loctite. My rifle's basically my take on the Recon Rifle concept so aVFG wouldn't really be appropriate. Anybody else got some ideas?

What's wrong with the PRI GenIII tube?

The rails have screws that connect to a "backer" inside the tube.   Just loctite everything and it won't be going anywhere.

Heh, the $320 price tag...

The PRI tube is expensive, but worth it IMO.  You can add almost as much rail real-estate as on a aluminum railed fore-end, or remove everything you're not using for light weight.

Yeah, you're probably right Zak. I'll just have to switch to TV dinners for a few weeks, then send my upper off to Adco to get the barrel turned down and the PRI tube installed. The weight of my AR is directly proportional to the weight of my wallet. As one gets lighter, so does the other.