How are handguns or military spending related to left/right politics?
Conservatives tend to be more nationalistic and in favour of strong border controls and security, including a strong military. Those on the on the other side of the political spectrum tend to be much more trusting of the good will of others and uninterested in nationalism or securing borders. In Canada, calls to downsize the military have always come from the Left, never the Right.
Gun rights tend to be a rural and thus more conservative issue. The Right feels the people who do bad things with guns should be punished. The Left feels guns are icky and so are those who own them. Again, in Canada, it is always the Left calling for stricter gun controls, the Right which opposes.