So I am going to build another AR but in a 6.5 Grendel. I really never looked or asked about the metal requirements for AR barrels before. Chrome lined or not? Stainless or not? Need input on anything else as far as type of metal.

A lot of that is personal preference. Each claims some advantage.

I have no idea about any of that, that's why I stick with stainless... and it's pretty

Most of the Grendels I have read about are not chrome lined barrels. Good source for Grendel information is at 6.5Grendel.com

Chrome lined:
Pro: harder bearing surface -- lasts longer
Pro: Very rust resistant
Con: this is a plating added to a surface that's been sized, so they can be less precise/consistent dimensionally. FN says their CM barrels are just as consistent and precise as a Stainless barrel though.

Stainless/unlined:
Pro: precision sized/lapped, nothing added after the barrel is dimensioned -- should be more precise.
Con: less hard bearing surface results in shorter life
Con: less rust resistant

Melonite treated barrels claim the advantages of both

Won't the non-chrome barrel be (marginally?) more accurate, typically? I wouldn't think you're going to shoot it out anytime soon. If you don't mind the shine, go stainless, otherwise 4150, right?

Gary, I would guess you are looking for accuracy so I would avoid the chrome lined as it is only there for durability. Stainless or Chromo, doubt there is any real difference in accuracy. Go with a MFG that is known for accuracy...very few actually "make" barrels.

Think you read my mind.

Take a look at Satern barrels

There are some very good barrel builders out there making 6.5 Grendel barrels. Bartlein, Lilja, Saturn, Criterion, Krieger, Shilen and Black Hole Weaponry (BHW). Barrels are also available from Alexander Arms.

Some of those will set you back as much or more as an upper from Radical.

not to hijack this tread, but where does chrome moly come into play?