I been using mobile 1 full synthetic. That's what I had in my garage. And I will probably be using the same quart until I die. I've never had a problem at all with it. For my sig, I mix it with a small amount of lithium grease for the rails and its perfect.
Boy who would have thaut the gun indertry is just like the marine and rv indestorys double the price by addind a none to the lable. I'm going to just top my gun oil bottle with some none derergent sae 30. After all gun oil does come in a nice handey lillte bottle that stores well in my cleaning kit.