The moly lubes often rank best because their coefficient of friction is lowest among the enduring lubes. The carrier is another matter. In the sandbox they've had millenia of wind-driven impact of sand-on-sand that makes it finer and finer until it makes a gun-choking abrasive dust that sticks to any remotely damp or wet surface lube, including CLP and others that are very good to excellent outside that particular environment. As you might expect, dry lubes and cleaners have gotten popular there. For example,
Mil-comm 25B (fluoropolymer-based) claims to be the only military-approved lube for Gatling guns (modern motorized, that is; not Civil War era). It is burnished into the warmed metal and ends up dry, so it doesn't hold dust. Gunzilla has become a popular gun cleaner in the sandbox and, if its web page is to be believed, has
ended a lot of malfunction problems. The way it does that is it dries to leaves a thin smooth lubricating varnish is dry.
Two I've come to like well in specific applications are MolyFusion and Plate+ Silver.
Moly Fusion is the ultimate dry lube. It is a micro-thin metal conversion process that leaves behind a waxy feeling semi-permanent coating of molybdenum-based phosphate. It is truly dry and dust can't stick to it at all. The coefficient of friction is a very effective 0.07. It has the advantage of working on aluminum as well as on steel. The drawback is that it requires heating (140°F or so) and a bit of practice and sometimes a second or third coat for the original version. There is now a newer more active formulation that is supposed to overcome some of that.
Plate+, is based on a patent licensed from NASA. Like Weapon Shield, it is an electronegative surface bonding synthetic lubricant which has semi-permanent properties. Plate+ Silver additionally contains micronized acid-neutralized molybdenum disulphide in colloidal suspension (it never settles out, except a very tiny percentage). You soak a piece of steel in it for 48-72 hours, at the end of which it is in place and not easily removable. No matter how dry you think you've wiped the metal, it is still there. As an example of its penetrating properties, there are several steel hinges in my house that used to squeak badly. I put all manner of conventional lube on them in the past, and after a few months they would start to squeak again and need fresh lubrication. I put a few drops of Plate+ on each of them. 90% or so of the squeak stopped right away, but after about two days it had penetrated and affixed itself to the metal, so all squeaking stopped and hasn't returned in over four years. The coefficient of friction is an astonishing 0.02.
The drawbacks to Plate+ are that it works only on ferrous metal and does nothing for aluminum. It also take several days to complete treatment. The company makes wheat they call Machine Gun Lube, which is a synthetic oil and Plate+ mix that is a general purpose gun lube, but would not be for the desert.