First, if you read the Supreme Court’s decision in the 1939 Miller case, it’s plain that a “militia weapon” is whatever the military is using at a particular time. Since, in 1939, the US armed forces were not using short-barreled shotguns (although they did in WWI and WWII), Miller’s shotgun was not a militia weapon.

The Miller decision means that M16’s, M4’s, squad automatic weapons and other now-prohibited guns are “militia weapons,” and should be available to US citizens. It will probably be years before a challenge on the National Firearms Act of 1934 and the Firearms Owners Protection Act of 1986 are challenged, they will be. And, if the philosophical makeup of the court resembles what we have today, bans on machine guns will be held unconstitutional.

As for the weaponry available in the 1700’s, few people are aware that there were already fully-automatic weapons at that time. The Puckett was a machine gun invented in 1715. (Oddly enough, it fired a square bullet).

The Heller decision is going to change a lot of laws over the next several years.