I just watched an interesting talk by Brian DeLay on guns and gun powder in the U.S. Civil War, Haitian Independence and the wars of Latin American independence from Spain in the early 19th century.
Delay pointed out that the revolutionaries in what became the United States did not have sufficient guns and powder at the beginning of the Revolutionary War to successfully win independence. The best estimate was 150,000 weapons in private hands (those households that had a gun, almost always had only one); powder was similarly in short supply. Most of these were not military weapons, and most households would not donate them to the revolutionary troops. There were perhaps 300 gun makers in the American British colonies, and they were largely craftsmen working alone to produce hand made weapons. (DeLay did not mention that much of the private stock of weapons and gunpowder must have been in the hands of loyalists. The Battle of Lexington and Concord occurred when British troops from Boston marched to secure the weapons and powder in the local armory.)
DeLay also pointed out that the imperial powers blocked the production of arms and powder in their colonies. At the beginning of the Revolution, the British blocked the sale of gunpowder to Americans. DeLay also underlined the difficulties of obtaining guns and gunpowder commercially, since mercantile trading networks were based on mutual trust among the traders. Not only would Americans need to find traders in continental Europe who would sell them guns and gunpowder, they had to pay for what they bought. This in turn meant establishing networks that would allow sales of US products (lumber, fish, rice, indigo, etc.) in Europe (other than in Britain). Robert Morris managed this for the Continental Congress early in the war, but the British found out what was happening and used diplomatic pressure and a naval blockade to stop the traffic.
Fortunately, the French came to the aid of the revolutionaries with large loans (essentially without collateral), weapons, and importantly gunpowder. (DeLay did not mention that due to the work of Chemist Antoine_Lavoisier, the French made better gunpowder than did the English at that time, giving the revolutionaries an advantage over their British enemies in gunnery. Probably the only American scientist of the time of comparable importance to Benjamin Franklin was Benjamin Thompson, later titled Lord Rumford, who was a loyalist. Thompson served with the British in the Revolutionary war, helped improve gunpowder, and emigrated from the Americas to Europe at the end of the war.)
After the Revolutionary War, the newly created United States gave high priority to its domestic weapons industry. The Sprinfield Armory was founded in 1777 to support the revolutionary armies. The Harpers Ferry Armory went into production as a government armory in 1802 The armories sought to develop local industries manufacturing weapons in their neighborhoods. The Dupont Gunpowder Mill was founded in 1802 by a former student of Lavoisier.
The Haitian Revolution (1791 to 1894) led to a demand for weapons and gunpowder from the Haitian revolutionaries. American traders were well situated geographically to supply that demand, and had the means to do so. American ships brought weapons and powder into Haiti for the revolutionaries, and it was estimated that there were 100,000 muskets in the hands of Haitian revolutionaries by the end of the war. While the tropical diseases were perhaps even more dangerous to the French regular troops in Haiti, the weapons in the hands of insurgents were also a significant factor according to DeLay. Sales were on commercial terms, and must have been appreciated by American commercial interests.
In the early 19th century, taking advantage of the weakness of the Spanish government, revolutions broke out all over Spanish colonial America. All of the revolutionary movements needed guns and gunpowder, and nowhere in Spanish America were production facilities available to supply the needed war materials. Naturally, representatives of many of the revolutionary forces showed up in American cities looking to buy weapons and powder. They did so at commercial prices, without government loans, often discounting paper from their revolutionary governments or offering commercial deals such as contracts for railroads. When the revolutions eventually succeeded, many of the U.S. merchants did very well indeed on their ventures.
DeLay did not emphasize the point, but it is clear that the new nation of the United States did well for itself by developing a weapons industry. Moreover, the Springfield and Harpers Ferry Armories played important roles in the development of industrial manufacturing in the United States.
I posted earlier on the Harpers Ferry Armory here and here.