What Precision Firearms is working on is a set of handguards that will fit on a NM free float sleeve, and clear the NM gas tube for it. All these things are CNC cut, so it's going to be a slight change in design (for strength), but will still be internally machined to clear the sleeve components. <thumbsup> Here's what the inside of the guards looks like now: The way these are machined now, they're closely following the standard gas tube - no way they'd clear the NM float sleeve and gas tube. Hopefully, the exterior dimensions won't need to change much, and look the same as they do now - or close to it. Again, guys, this is for the AR-15-sized rifles, as far as what fits. Transferring it all over to the Big Brother will be trial and error (and parts/dimensions matching) on your part. If what you have is from an AR-15, or fits an AR-15, then this stuff should do the exact same. <thumbsup>