"I think that it would be best for the proliferation of our gun rights if we kept our guns and our religions separately. IMO"
Aside from several comments others have made, I also will state, that having separation between your religious/spiritual "you" and your secular "you" is in essence an affront to God(or in most other religions whatever entity you believe in), and more over a deceit towards your fellow man.
One cannot simply turn on and off faith like a light switch. It is a part of that person, as much so as their ability to reason, or emotionally feel, or perform math, or read/speak language perhaps even more so than those other abilities since our spirit is eternal.
Simply put, I cannot stop being Christian me, in order to be secular me. I am simply me.
One cannot sideline their faith and then claim to live a faithful life in a secular fashion. Either their actions are contained within a framework of faith or they are not.
It is generally why I find it laughable when politicians who claim to be believers in any faith, state that they will not allow their faith to interfere with their ability to govern. It would be just as laughable to hear them say "I will not allow my ability to feel emotion to interfere with my ability to govern.".
And without meaning to sound all Zen like, the trick is not to seperate or compartmentalize your life in order to make certain aspects of life convenient, but rather to find a wholistic approach to living in which all aspects are in balance and support each other and are contained within a framework of faith.
Ultimately how this pertains to self defense and gun ownership, if I have to defend myself, my loved ones, or an innocent with lethal force, I know that I will not be blemished in the eyes of the Lord for that action.
And when talking to fellow Christians about this topic, I find scriptures that plainly support that view to be comforting and instilling of my confidence to exercise my right to self defense and defense of innocents.
When talking to non-Christians about why I choose to defend myself, I have to honestly say that my religion plays a part in why I have my stance(it is the truth afterall), and that at times can open the door to witness to them as well.