Hoppes 9 for cleaning and Mobil 1 synthetic for lube. Why pay for ounces when you can buy a quart that will last you a lifetime. If it can protect an engine, even hiigh performance engines, for tens of thousands of miles I feel it's okay for my guns. And it's never given me a problem.
I don't know about using Mobil 1 synthetic motor oil. I personally think it's silly. Here are some of my reasons why.
I own 7 firearms and spend a decent amount of time at the range, by the way.
First point: I have a small 4 ounce bottle that cost about $7 that I've used for about 4 years now on all my guns. That's about 50 cents a year. If you can't afford that, how do you afford ammo?!?
Second point: motor oil is designed for use in a closed (sealed) engine compartment system. A firearm isn't a closed system. So, it makes sense to me that motor oil engineers don't worry about attracting dust, dirt, etc., because there isn't any in a closed system.
Third point: motor oil is engineered for extremely high temperatures under pressure.
Fourth point: gun oil is engineered to perform under the typical temperatures and lubrication needs of a firearm. It is designed to penetrate the tight spaces on a firearm. It is designed to not have a tendency to attract and hold dust, dirt, etc. It is designed, in other words, for a firearm.
Would you buy a gallon of gun oil and use it in your Mercedes Benz? Why not?