I am new to the AR15 scene.  I just bought my first.  It is a Bushmaster V Match 20".  I have some experience with M16's from when I was in the service over 30 years ago and we removed the plastic hanguards to clean and lube under them.  Now I have the aluminum free float handguard and it doesn't look easy to remove for regular maintenance.  What are you guys with the free floats doing???

I spray rem-oil on the outside of the barrel from the muzzel end of the float tube.

I have had the rifle since 1997 and so far so good when it comes to rust on the outside of the barrel.

I have the same gun, I use a 12 gauge bore mop on a couple of sections o' rod and by the way, welcome.

welcome garyw.  i lube the barrel with a little high-temp grease before i install the fft.  unless dirt or water gets in/on your gun it will only need this about once ever couple years.

You're right about the BM 'V-match' HG they are next to impossible to remove.  Don't bother trying unless you plan on replacing it.  I couldn't find any standard barrel nut wrench to engage the indexing holes.  Wound up having to use a  strap wrench.  
I just sprayed 'Sheath' liberally under mine and swabbed out the excess every once in a while.