I'm agreeing with Motorhead 100% on the Bar Oil. You want a lubricant that well, lubricates without dispersion or adverse effects to the materials of the 0-ring. A good synthetic, I just happen to have Mobile One laying around. I use it in my shops machines, high speed embroidery machines. My lubrication times have gone from every few hours to monthly. The Belleville stacks have a range, a minimum and a maximum, need more, use thicker, want less, use thinner. By having them uniform you spread the compression force equally between them all. It matters not one bit if you have one reversed at the top or the bottom of the stack if you have an odd number stack, it just needs to be fully seated. My thought on synthetic oil is, if it's good enough to keep a F1 car engine running, it's more than good enough for my air gun. Plus I have a very bad experience with silicon, may have been a one off but not taking any chances. I want things slippery, if it moves or slides, it get M1.
