PCP & Lubes

Divers grease for lubing orings and 100 percent silicone oil for regulaters etc. Each gun is slightly different so I would go on youtube to learn how much and what viscosity of oil you need and where. However inside the air tube you need silicone only because if you use gun oil or something flamable you will turn your gun into a grenade. I tend to use the divers grease on my marauder and oil on my pump. I just drop a bit at the air intake and a couple drops on the pump orings every 50 to 75 pumps. 
 
Very light use of silicone is fine for O rings, provided it is a sufficiently light coating that it cannot migrate to any high pressure threaded connection. It is not a lubricant for high pressure connections, and can cause seizing of the parts. Upon the recommendation of a high-end air gun maker, I use synthetic Mobil 1 oil and grease for lubrication on, or close to high pressure connections. A quart of each will last a lifetime.