A well regulated Militia, being necessary to the security if a free State, the right if the people to keep and bear Arms shall not be infringed.
What is a militia? Today's Militias are the Air Force and Army National Guards. They can be sheriff's posses and reserves. To be a true militia, it must be under the command and control of an elected official.
Before WWI, many states had formal Militias. They were citizens that joined military units under the command of that state's Governor. They could be called up for local emergencies from Indian uprisings, civil unrest, or natural disasters. The President could nationalize these forces for national emergencies. This has been done many times in the past and is done today.
There are many citizen groups that claim the title of Malitias. In my view, they are true militias ONLY if they are under the control of an elected official like a Sheriff, Mayor, or Township Supervisor. The rest are citizen groups. While their motives may or may not be good, they are not Militias in the true since.
Back when the Constitution was written, the musket a citizen owned was also his Militia weapon. Today, the improper term "assault rifle" would describe that weapon.
Today, it takes a bunch of Federal paperwork to own an M-16A-2 like I carried in Iraq. It is possible to do this. You won't find this weapon in any gun store.
The look-alikes you will find in most gun stores lack the third function. That function is Auto(matic) or Burst. The civilian versions have only Safe and Semi(automatic).
A short lesson on weapon terms for those that don't know.
Safe means the weapon will not fire when the trigger is pulled.
Semi means the weapon will only fire one round when the trigger is pulled.
Burst means the weapon will fire very quickly three rounds with a trigger pull.
Auto means the weapon will fire until the trigger is released or the magazine is empty which ever comes first.
Again, the last two functions are not on civiliam look-alikes. You won't find weapons with those functions in a gun store. You would have to special order it. The seller would have to check to insure you had all the proper permits before he could sell it to you. Plus the seller would have to have similar permits to be able to have the weapon to sell it.
There is much dispute as to what an assualt weapon is. To too many in DC, it is any weapon that looks like a military weapon reguardless as to how it works or the rounds it fires. They are trying to apply this term to any weapon they don't like based mostly on looks. That is wrong. So let's be clear, you can't buy a military weapon without a ton of paper work.
The weapons I trained with in the military are already very regulated now. You can not go to your local gun shop and buy one. You must have Federal Permits to purchase and own weapons capable of Burst or Automatic firing. So more regulations to ban or restrict these weapons are not needed. The regulations are already in place and working.
Since the weapons back in 1787 were "military" type weapons that an individual did use when training with their Militia, doesn't that argue that citizens that are part of a true Militia could buy the same weapons our military issues today?
It was also true that more than a century ago, when a militia (National Guard) member retired, the individual got to keep their issued weapon. I wish that was still true. The M-16A-2 I carried in Iraq was a fine shooting weapon. I scored expert with it twice.
It is also true that before the Defence Reorganization Act of 1947, National Guard members that retired didn't get any retirement pay. Maybe trading my weapon for retirement pay isn't such a bad deal!