stick to one's guns - [informal] refuse to compromise or change, despite criticism: we have stuck to our guns on that issue.
Amer. Her. Dict. of Idioms:
stick to one's guns - Hold fast to a statement, opinion, or course of action, as in The witness stuck to her guns about the exact time she was there.
This expression, originally put as stand to one's guns,
alluded to a gunner remaining by his post. Its figurative use dates from the mid-1800s.
more definitions and examples:
to defend an action or opinion despite an unfavorable reaction
to be adamant
not budge ... "Stand by one's guns" is the British version of that idiom
If you stick to your guns, you show determination when faced with opposition. The government stuck to its guns in spite of the criticism.
hold to your convictions and rights. (Random House Dict. of Popular Proverbs and Sayings, 1996; quoted at http://www.phrases.org.uk/bulletin_board/12/m...
The teacher tried to convince Ronald that he was wrong, but he stuck to his guns.
to stick to one's guns - nicht nachgeben; festbleiben
stick to one's guns - auf seinem Posten bleiben; (fig.) auf seinem Standpunkt beharren
Republicans are hoping Democrats stick to their guns and allow the minority a stronger voice on legislation. (NY Times)
"In principle, we were right to stick to our guns over Owen," Beckenbauer is quoted in the Daily Mail. "If a player has signed a new contract with us, then tries to move for more money, we are within our rights to say no."
Ken Livingstone should "stick to his guns" and not apologise for his "Nazi" comment to a Jewish reporter, Tory MP Boris Johnson has insisted.
"It was a long road to publication. ... when they saw the length and realized that the subject matter was, in fact, as depressing as it sounded in its original incarnation, I would have thought... they decided they wanted something shorter and more personal ... I stuck to my guns, went back out on the market with a finished book -- the book that just won the Pulitzer Prize, I'm now very pleased to say" (Samantha Power on PBS)
Avoid paying your fare with large bills -- invariably, taxi drivers claim that they don't have change, hoping for a bigger tip (stick to your guns and give only about 10%).
_______________________________________OT: It would have been better to ask this in the Deutsch Gesucht section, then there would have been a field for sources and examples.
It's a perfectly normal expression, used in all sorts of contexts. You can find plenty of examples online. If you want to check the register, limit your search to the website of a publication whose style you trust, like PBS, the New York Times, the Guardian, the Economist, etc.
You can even find occasional headlines where the phrase has been used humorously to mean that people refuse to give up their weapons:
Somalis stick to their guns (LA Times)
Nepal's Maoists stick to their guns (BBC)
But of course that's only a play on words. The idiom is only figurative; in and of itself, it has nothing to do with literal guns.
I actually disagree with the Oxford-Duden translation 'auf seinem Posten bleiben' -- that was the historical source of the phrase, but AFAIK it's no longer used in that sense today, only figuratively.
If German speakers could agree on a translation, this would be a good New Entry. However, none of the suggestions so far seems quite right to me.
It's not really about being true to principles or roots, and it doesn't mean just to keep doing something in the sense of working, not stopping an action.
What it means is to defend a position or opinion in the face of opposition -- really, just to refuse to change one's mind (in a positive sense). 'Be adamant' and 'not budge' seem the best among the definitions I found.