I became more interested in firearm lubrication when I bought my SA NM M1A. I paid a lot of money for this rifle and I wanted to use a quality lubricant for it. I don't care about brand name; I just want something that works very well.
I did some online research on this subject and found some interesting results. Mobile 1 was actually found to be a very good lubricant for firearms. Think about it, the internal moving parts of an internal combustion engine are subjected to more stress, pressure, heat, friction, etc. than a semi-automatic firearm. Someone earlier said they don't like mixing up firearm and automotive engine oils. Many if not most of the "gun" oils out there are just liquid oils with a "gun oil" label on them. The same formula is sold with a different label for use with other equipment. There is really nothing special about them as far as firearm applications go. Sure, as with all products, some work better than others, but just because a product is labeled "gun oil" doesn't mean it provides specialized lubrication for a firearm.
For my M1A I ended up using a synthetic aerosol lubricant made by Energy Release that is designed for cables and chains. It comes out as a liquid and quickly turns to a clear grease. It sticks to metal surfaces under stress and heat better than anything I have tried. I wouldn't hesitate to use Mobile 1 also.