Cleaning up black powder guns requires water. But, leave 'em guns too clean with no rust protection and presto, RUST. The reason Ballistol works is that it leaves a film of rust preventative behind.
There may well be other products that do the same thing. I'm thinkin' of tryin' water pump lube just for grins. The thing is, clean with water and leave some lube to cover the metal. Clean metal with a film of oil doesn't rust. Clean metal with no protection flash rusts pronto.
So, clean those BP shootn' irons with water, but don't leave clean dry metal to the elements. Oxygen and Iron quickly get together to form Iron Oxide. . . . rust. The oil film keeps the Oxygen from getting to the iron.
That's the nut of it. How you do it don't matter as long as when you're done the clean metal is protected with a film of rust preventative oil.
Not all oils are equal. Some evaporate in time. Others congeal and make a sticky or varnish like mess. Go with an oil that stays the way you want it.
Good luck, make smoke!
DD-DLoS