'Break-Free CLP' - that's what the Army supplies and has for a long time, because it 'works' and it's been working in some austere environments as well as some moist ones.
This conversation is beginning to sound like one of those Civil War ones where everybody's trying to out-do one another in 'their' idea of 'authenticity' - as in:
"I'm more period-correct than you, because 'I' (bright little star that I am) lubricate 'my' firearms with sperm oil...' (But I'll never mention that I shoot Ruger Vaqueros and Marlins and products of the entire manufacturing regions of Sunny Italy...)
Lubricants changed over time - each becoming better at both cleaning, lubricating and preventing rust - use them or don't.
I guarantee you that if it appears in print in some 'Old West' magazine, or any C&WAS rag that 'someone, somewhere's buddy's brother-in-law's high school kid's janitor's cousin knows a guy at the gun shop whose Great-Granddaddy only ever oiled his shootin' iron with butter, a man would be wise to stock up - 'or' argue that margarine spread was better...
Scouts Out!