Having serviced many thousands of those rifles..
Stepping outside the Military box for a moment..
Those things mentioned up there all work, but If you run things on the dry side, I highly highly recommend Militec.
For me, from days where I put 500 rounds down range to the days I put 25 my lube points are the bolt cam. The raised ridges on the bolt itself and a light coat on everything EXCEPT the bolt face. The bolt carrier on the contact points in the metal get a good coat. Top and bottom. This will generally be all you need, I have had one incident in the civilian side where I had a hiccup in operation. I fired off about 100 rounds of obscenely dirty ammunition, both on the cases and the propellant was not fully burning.
On the Military side, I've seen rifles choke for a non mechanical fault in two situations.
Run bone dry for several hundred rounds in the blowing sand of Iraq and Kuwait.
Soaked with too much CLP. Shot in by the squirt bottle full till it dripped off the parts. That will also attract your dirt and propellant residue. It can also bog down your locking of the bolt, either preventing it from going fully in to battery, or in one incident it created a near hydrological seal and it was not popping free reliably with out breaking the seal on the upper and lower receivers.
Really, put your favorite flavor on there. I again recommend militec but other than that, a light coat on the bolt and bolt carrier and you will not go wrong.
Regards