Quote Originally Posted by Jordanls19 View Post
I'm a huge supporter of the "if it slides grease it, if it pivots on a pin oil it" movement.

I use some old Garand grease on just about everything I own. I do have to "water it down" with some MilTec or WD-40 for my lighter recoil (.30 carbine) weapons but haven't had a problem yet with my garlands or AR. .

^This.
Look at the way the load/pressure is applied to the part in question. If it is a sliding fit then whatever lubricant is subjected to shear loading. Grease resists being displaced by shear loading/pressure much better than oil. All the lube in the world will do no good if it doesn't stay where intended.
Hence if it slides grease it-if it turns oil it.
I am a firm believer in the benefits of synthetic lubricants. They keep their viscosity consistent regardless of temperature.
I am a firm believer in Tetra products or Magnalube. The one big thing I have noticed with either is stainless steel has not galled when using them. A nice benefit to the Tetra oil- I have found that if I wet patch the bore, gas piston or bolt carrier/bolt and leave it slightly wet the clean up next time goes much quicker and the bore does not seem to copper foul as much.
Mobil One also performs well but I would not use the ATF, it has a high detergent content and is more like a hydraulic fluid instead of a lubricant. Works great as a cleaner (Eds Red solution) though.
Glock recommends a copper based anti-seize compound-it stays put and is excellent in shear loads. A little dab will do.
Less is more when it comes to lube. You just want enough to see it in place but no blobs or drips.
As far as thinning out grease I would use a light oil such as 3in1 or a light motor oil, stay with a petroleum product for it as that way it will be compatible with the older Mil grease.
NEVER use WD-40 as a lubricant! It is essentially a silicone based oil suspended in a carrier (kerosene/mineral spirits) when the carrier evaporates you will end up with sludge. It works ok to displace moisture so keep some handy when you go on a duck hunt and dunk your shotgun, just make sure you clean and lube properly when you get home.
CLP is about like a 3 in one shop machine. It will do a little bit of each, Clean, Lubricate, Protect but nowhere as effective as a dedicated bore solvent or lubricant. About the only thing I use it for is "Armor All" for firearms. It works well to keep a finish fresh and dark, especially after I did some work that required de-greasing etc.