If every human person has a natural right to life, then he has a right to defend his life against those who would seek to violate this right. This means that one has the right to an effective method of self-defence.
Unfortunately, this denies the possibility of non-lethal methods of self-defence or acknowledge their efficacy. If effective non-lethal forms of self-defence are aailable, then a person who believes in the right to life should be using those over deadly force.
How about, people have a right to life. All people have a right to life.
They have a right to self-defence, but deadly force is an extreme option. It is the ultimate last resort if you believe that life is sacred.
If one states that there is a right to life, which is more important life? Or the ability to use deadly force to defend your life? Is one person's life more valuable than anothers? Is the possibility that you could harm or kill an innnocent bystander outweigh your own life?
By arguing that deadly force is the first option, one removes the legitimacy of stating that one has a right to life.
I have a right to life, but you don't. Does this make sense?
In fact, the right to life position is totally anti-thetical to the current "no duty to retreat" theory of self-defence. Right to life is in accord to the "back to the wall" theory of self-defence, where every opportunity to avoid, deescalate, and/or withdraw from the situation has to be eliminated making deadly force the LAST option.
The right to life position means that a reasonable person would use reasonable force to end the threat; not deadly force. This means that non-lethal methods are the method of choice, not ones using deadly force. Especially if deadly force could result in harm to innocent bystanders.
If pepper spray is an option, then you must use that rather than deadly force. I find that pepper spray works quite effectively for ending threats. It allows for one to retreat to a point of safety and prevents the possibility of harm to innocent bystanders.
Likewise, everyone has a right to life, therefore, we should work to remove situations where violent confrontations arise. This means that social programs that work to reduce factors that would lead to crime are a priority as well to someone who claims that there is a "right to life".
By eliminated the possibility that non-lethal defence as an option, you have removed any legitimacy of your claim to being pro-life. Life is not sacred, you may kill. You do not believe that you need to first avoid conflict and secondly, had taken reasonable steps to retreat and so demonstrated an intention not to fight before eventually using any kind of force: deadly or otherwise.
Sorry, but being pro-gun is totally antithetical to being "right to life" since that means you believe deadly force is an option. You cannot believe that life is sacred, yet be willing to take it.