I've found that synthetic 2 stroke oils work better than synthetic motor oils. It doesn't produces less carbon when it's burnt (AR bolt carriers), it sticks better and doesn't sling out, and it comes in cool colors (orange, red, blue, purple) just like the expensive gun oils (because most of them are just repackaged 2 stroke oils). Motul 800, ELF HTX976, Castrol RS TTS, Maxima 927, Bel-Ray Si-7 are all very good oils.
And just for you guys that religiously change the oil in your vehicles every 3,000 miles.
Stop Changing Your Oil