I know this should be posted in the AR forum but, hey what the hell it is the GD.  Any who, is it really worth spending the money to free-float the barrel of an AR?  $250 is a lot for two pieces of plastic.  I know that there are cheaper free-float tubes on the market but they are mostly 1 piece tubes which involve taking the barrel and the FSB off.  For a defensive carbine I don't like the fact that it would take a helluva long time to replace the gas tube should it need replacing.

Unless you are in a 1903 competition type sling like we use in highpower matches it is a waste.  My single point sling on my SHTF gun puts no stress on the barrel!

I've freefloated my scoped 20" AR, so that the barrel is completely free from being affected by the sling or bipod.

Not sure I see the purpose for a defensive carbine, unless it is to mount some kind of laser or IR designator that needs to be perfectly aligned with the barrel/ballistics.  For something like a defensive carbine, I'd be perfectly happy with a 2-piece set up like the $100ish YHM or MI railed handguards.