An Example Why AR-15s should be limited use

[petronius]

46. They *were* privately-owned warships; the letter of marque didn't give permission

to own the ship, it gave permission to use the ship to capture certain others, and not get hanged as a pirate for your trouble. The supplies, armaments, etc., all came from the private market and were provided/obtained by the ship-owner. But if you weren't operating as a privateer it would have been legal to own a private 'warship,' as long as you didn't go around attacking people with it. (Not a particularly lucrative thing to own perhaps, absent the privateering, since guns take up space that could be used for cargo and require bigger crews. But for trading into more dangerous areas, or smuggling, a well-armed ship would have been wise.)

As for the general question of cannon ownership, it would not have been uncommon for a merchant ship to have cannons, albeit probably not those of a class to stand up against a modern warship. So the Founding Fathers would have have been completely familiar with cannon in private hands, and maybe owned some themselves.

Not to mention that those privately-owned cannons were probably rather important at the beginning of the conflict, given that the British weren't keen on sharing theirs. So, privately-held artillery would have been one early source for the Continental military, along with what could be privately purchased and what could be captured...