This discussion is similar to the debate of whether or not it is "Christian" to fight in a war. Many "believers" who are also soldiers have claimed to believe that this is a constant struggle for them.
I tend to believe that though the Bible is provided as a book of love and wisdom for the followers of Christ, God created humans with the capacity to think and reason beyond the confines of words on a paper and the opinions of others. There are hundreds of concepts in the Bible that can be looked at legalistically and hypocrite finger-pointing could go on all day. The bottom line is that every human is called to use his brain and his heart (together) and to act accordingly.
As such, I don't think gun-owning Christians are hypocrites. God