Interesting point. Though, I don't think it would be a free for all. The gun owning side would be less organized at first. The side without the guns would be funded, as usual, and thus coordinated by a centralized party. Propaganda would suggest it's an organic militia, but it would in fact be supported by a central entity. This would cause the gun owning side to form ranks. Thus ending up with a 1v1 style civil war. Again, I think it would still collapse pretty quickly.