Is the problem powder residue sticking to the works when they get hot
or that talc-like dust combining with the powder residue?
I also understand that the M4 action won't cycle when muddy?
And what is the commercial name of the lube you recommend. I like Dry-Slide, but by now there must be something sexier.
The entire upper receiver is coated with a teflon material.
The residue from propellants is not as much a problem as some make it out to be. Graphite is commonly used as a lubricant, and this is the bulk of the residue we are concerned about. Graphite is used a a retardant on the ball powder used, the issue is that the original specifications by Mr. Stoner called for IMR (extruded stick powder), which uses different chemistry to control burn rate, and produces less residue (usually).
The dust is a problem, but with proper lub, routine cleaning and common sense operator sheilding of their weapons, and good junior leadership, dust can be kept to a minimum. A magazine in place, dust cover closed, muzzle cover on, the M4 is pretty well protected.
Not sure of an equivalent dry lub available commercially, but the mil-spec is a tough coating that in my expereince lasts quite a while under hard use, I will look it up and see if I can find a mil-spec nomenclature.