The right to bear arms was officially set up in America AFTER the British were defeated, so clearly, the purpose of the second amendment was not to fight the British. Here is the second amendment: "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." First of all, there is no mention of the British!
There
is something called the War of 1812, so it's not like the British just poofed after the Revolutionary War concluded. You also have to take into account when the Second Amendment was written. The US did not have a strong army at the time, so most of the fighting was done by militias. Much of the US was still a frontier, and there were hostile Native Americans ready to fight Americans that tried to settle their lands. Although the French allied with the US during the Revolutionary War, the French were eager to undermine the US and egg on hostile Native Americans, and the British, who still retained territory in America, were keen to do the same. Under these circumstances, it would be very logical to carry a gun around, especially in the frontier.
Secondly the purpose of the right to bear arms is made clear, that it is for the security of a FREE state. You see, in a truly free country, an overpowered police force/martial law cannot be tolerated, as such, a militia, or a band of armed citizens are the main peacekeepers. I am deeply disturbed that you think such a concept is outdated.
On the same token, if the US was a truly free country, we wouldn't need people to represent us, e.g. House of Representatives, the President, etc. The US army and police forces are much more powerful than they were back when the Second Amendment was written, so I think it is safe to say that we don't need a body of armed citizens to keep the peace. There are such things called Neighborhood Watches that report to the police when something is fishy. Whether or not they are effective depends on how eager residents are to cooperate.
Of course gun-related homicides went way down after the UK banned guns, but knife-related homicides went up. With that said, it's still way harder to kill someone with a knife than with a gun, and gun control
may reduce the number of robbery-related homicides.
While I think that the second amendment is definitely necessary, I do think that the accessibility of guns should be reduced. We don't need violent individuals or organizations having access to firearms.
The question is where to draw the line. Some criminal organizations may obtain their firearms from friends or family members of age that have no criminal record.