Its certainly possible to be a social conservative and a libertarian, but its much easier to appeal to social liberals, because it would be for legalizing the types of things that they do, so obviously they are going to be for that. If your going to convince social conservatives to be libertarians, you going to ALSO have to convince them to not want to force their social conservatism onto other people.
Same with the military. Its waaay easier to appeal to the anti-war lefty folks, that is much more in tune with libertarianism than people for a ‘strong military’ The American military is probably 100 stronger than it would ever need to be.