Go with reality. Obviously, someone who will never allow guns in the home wouldn't be a good fit for someone who likes to keep and bear arms.
I grew up in an anti-gun home (single mother who was opposed to having even a BB gun around). By default, as I became an adult I was anti-gun, but it was a taught value not one based on experience, facts, or core beliefs. As I have gotten older, I've come to understand the 2nd Amendment better, and strongly believe in the right of people to defend themselves.
When it comes to dating someone, I think you should look at your core values--those things that you feel strongest about--and not focus on the things that are not part of that core. You don't neccesarily need to agree on every belief, just respect each other's beliefs. If you found someone who may not like guns, but thinks it's okay to own them (like my dear wife), then you probably will be able to build a relationship on your shared values.
When it comes to core values, I believe there are 4 legs that a lasting relationship stands on:
Religion
Family
Finances
Intimacy
At any given point in a relationship, one or more of those things will be strained. If one part of the relationship is strained--for example, finances suffer because of a layoff, etc.--then the other three legs of the relationship keep everything in balance.
Certainly, owning guns can affect these values (especially the finances these days), but as long as you can agree that it's okay for you to own guns even if she doesn't like them, then it shouldn't be a problem. Just check the core values before you go to the next stage in a relationship.