The United States military is not allowed to bear arms in the confines of the united states or it's territories, this is what a well trained and outfitted militia is for, according to the constitution. 
The second amendment is what give's individual citizens this right.
The national guard, commanded by the general's appointed by the individual state's governor commands the only military arm allowed to bear arms on us soil.

Everybody needs to quit repeating the stupid thought that the second amendment is for hunting, it was another check and balance put in place to keep the federal government from becoming more powerful than the individual state's.
It also amazes me that people boast that the world is changing and they quickly dismiss and want to abandon the documents that allowed this to happen....
The US Constitution and The Bill of Rights please read them and congratulate our forefathers and thank those who have fought for or died for people to express their opinions like yours.