I think it's gonna be one of those where you torque the nut on, thread the handguard all the way on, then back it off until the rails align, then lock it in with the set screws on the side (I'm probably waaaaaaaaay off, though). Hey, lovetabike, do you have a mic? If you do, measure the width of the gap on the barrel nut. The teeth on my wrench are approx. .185" wide, would that work? If it's too small, or if you can't find a wrench from Christensen, you could probably use something like a single pin spanner or castle nut wrench, but if you're like me and want one made specifically for that nut, you could always send your barrel nut to someone and get them to make one for you. I might know a guy.... :D