I have already learned so much just reading other posts here I think I can build my own AR.  
I do have a question that I have not seen yet:
Can you put a free float hanguard on a mil-spec barrel? Do you have to remove the front sight and the front handguard bracket?
I am wanting a free float but like the prices of the mil-spec barrels set up for the standard hand guard.
Thanks for your help.

It depends on what type of FFHG you want.  If your looking at the traditional and simple aluminium tube type, then yes, the frontsight, delta ring, barrel nut, and any muzzlebrake would have to be removed in order to install.  

If your budget allows however, you may want to look at the civilian-SIR or RASII series.  They will install onto your rifle as is, no barrel removal/barrel component removal needed.

Tex78

 Thanks Tex,                                 Are the aluminum tubes worth the trouble, or are they just a cheap piece of nonsense?

depends on the type of shooting you like to do.  Any FFHG will (in theory) improve the potential accuracy of your rifle.  The tubes will do this well, and for litle $$$.  There are some downsides though. Aluminum tubes dont get ventilated well, and can get uncomfortably hot during extended firing, though if you are slowfiring for long range accuracy, this my not be an issue.  They are also dificult to add do-dads to, should you need to.  One-piece 4-rail ffhg's like those sold by c-more, olympic, bushmaster have similar install issues, but are at least easy to accessorize with all the weaver-rail-mounting good stuff.

All depends on what you want the rifle to do.
Myself?  I would leave the tubes for the target rifles, and go with a 4rail or regular guards on any defense/utility rifle.

Tex78

Sound like what I was thinking. Would the factory 2 piece stock with rails that bolt through the vent holes be dependable bouncing around in a truck?  Or do I really need one with the rails built in?

I disagree, I think free float tubes are the only way to go. They are very easy to remove for cleaning etc. And when I burn through some shells and want to cool off my gun I simply unscrew the tube and remove it, cools really fast.

And standard handguard are a pain in the ass to remove and put on. They are less accurate and I don't like the plastic.

Even the tactical freefloat simply thread on and you use the indexing nut to get them just where you want them.

You cannot use a standard front site tower if you plan on taking off the tube often though. So you would be better off getting a gas block with removable sights or using a scope. I milled off my A2 tower and painted it. Looks great and my tube slips right over it.

A standard freefloat like a DPMS will run you around $50, a tactical tube will run you about $125. The beauty of a free float is you can also get them vented or drill a bunch of holes in them yourself.