I'm a geolibertarian and I am pretty much in line with the principles espoused by the Democratic Freedom Caucus (a geolibertarian faction of the Democratic Party) and I am in agreement with most of what they promote, but I'd like to know the range of possibilities that a libertarian can stand on gun control.
Here is something to consider. The gun argument requires that you argue from the general to the specific. If a "libertarian" believes that generally the government should not unnecessarily restrain the people then regulating guns at all is an unnecessary restraint of the people. You can see the obvious problem with this argument.
You are encountering an American belief (gun ownership) that is actually unrelated to libertarian-ism. The concept of "harm" would apply for a libertarian, would it not? Mill Said:
That the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others.
That is the very definition of the purpose of gun laws. Taking Mill as an authority (and he is a very good one) you can see that it is perfectly acceptable for a libertarian to accept gun laws in service to this ideal... That they are designed to "prevent harm to others".
The American Libertarian Party said this:
Criminal laws should be limited in their application to violations of the rights of others through force or fraud, or to deliberate actions that place others involuntarily at significant risk of harm.
So I will use the absurd arguments of others. I could argue that storing rockets in your home could involuntarily place others at significant risk of harm. A fire at your house for example could blow up the neighborhood. Therefor there is no problem with a libertarian supporting a government ban on the private ownership of explosive rockets.
But that is begging the question a little. What about the public's right to carry a pistol concealed in a crowd? I, and many others would maintain that absent very considerable training on when and how to use a firearm this action puts others at significant risk of harm. I could maintain that allowing violent criminals access to firearms DOES put others at significant risk of harm. Therefor as a libertarian I would favor limitations on who might possess a gun and where and how they might carry it.
You can see the harm principle at work in the issue of free speech as well. It is not held as absolute. Though pains are taken to not limit political and artistic speech, there ARE limits to what one might say or print. Likewise with religion. There are limits to the practice of religion. Libertarians rarely, if ever, wail as loudly about those as they do about guns.
Finally there is this. Any person's political positions ought to be viewed first through the lens of what one believes to be right and wrong. It is far less important for my beliefs to adhere to conservative talking points than it is for them to simply make logical sense. If a position makes sense then one may choose a label for ease of reference. But you are a smart person. Your intelligence is not to be used to try and fit an ideology but rather to be used for you to formulate your own. There should never be a dilemma like this:
"I do not think it is wise for untrained people to carry guns in public but I have to favor it because libertarians (and I am a libertarian) think it is a right." It is not only acceptable but also a sign of wisdom and intelligence to depart from party orthodoxy and embrace the "right" position.