Gun oils, despite advertising claims, have no special ingredients or formulations specific to firearms. The interior of an automobile engine is a much more demanding and extreme environment, in terms of mechanical wear, oxidation, and chemical breakdown of lubricants.
They can get away with a lot of stuff with firearms lubricants that would be non-starters in the automotive world. Like "Fireclean" brand CLP, which turned out to be vegetable oil. Like "Froglube," which turned out to be coconut oil plus food coloring plus oil of wintergreen. Between that and the fact that I can get a quart of big box store brand full synthetic motor oil or gear oil for less than the cost of a 2oz bottle of CLP, I figured it was worth trying. Likewise, synthetic wheel bearing grease of the kind you can get in big plastic tubs for under $5 is outstanding on slide rails, and as a general purpose lubricant on older firearm designs like 1911s or Garands. Even cheap light-duty white lithium grease is fine in these applications, and even used to be recommended for stainless steel firearms back in the 1980s. The only place they might be lacking is suitability to extreme cold weather.
Low temperature synthetic greases are tricky and expensive. Lithium, calcium, and aluminum stearates are cheap and perfectly okay for normal temperatures, and extremely heat resistant, but the gels they form with oil become too thick and sticky and their thixotropic lubrication properties are lessened in extreme cold. The best thickening agents we have for low temperature is things like calcium sulfonate or calcium tosylate, which is expensive, and the gel it forms with oil begins to melt at only a bit above the boiling point of water, where even cheap lithium based grease keeps on working up to the melting point of lead, or higher. The most suitable synthetic lubricant oils we have are things like low molecular weight, short-chain polyalphaolefins of the sort used for low-viscosity, low-temp synthetic motor oils. There are low temp synthetic greases made to this exact recipe, often with molybdenum disulfide added to boost load carrying capacity in extreme high pressure applications. The recipe is known and lots of companies make low-temp grease answering this description. And they're all expensive, and their sensitivity to heat makes them ill-suited to general year-round use.