In terms of accuracy and reliability, the firearms produced in the colonies were fully the equal of, if not superior to, anything made anywhere in the world.
While French aid was invaluable, it is mere supposition to state that "without this assistance, it is doubtful if even the small army which Washington then commanded could have been kept under arms."
The truth is, Washington had managed to maintain his army in the field for six years before the French entered the war, thank you.
The truth of the matter is, the British military was over-extended even before the French entered the conflict. These forces were committed to defending a vast network of colonies scattered all over the world. The British might have withdrawn forces from India or the Far East or the Mediterranean, but this would have left their colonial assets and trade routes vulnerable.
In addition, the Americans had already inflicted significant defeats on the British at Saratoga, in the Ohio River Valley, and American privateers were causing severe losses to the British merchant fleet.
By 1780, the British were finding it increasingly difficult to operate at large in the American countryside. Americans had perfected the art of insurgent warfare and guerilla tactics. Washinton's forces had gained greatly in military discipline and tactics, due in large part to the training instilled in them by foreign officers such as Baron von Steuben, the real father of the American army. The argument could be made that, after von Steuben cursed the American troops into shape at Valley Forge, that the Continental Army was never again in danger of dissolution.
It wasn't the French that inflicted murderous casualties upon the British at Saratoga, Cowpens, King's Mountain, and Guilford Courthouse. The difficulty in running American armies to earth is one of the main reasons that Sir Henry Clinton was content to maintain control of New York City. And perhaps the only commanders to produce original tactical thoughts on either side of the war were Daniel Morgan and Benedict Arnold. In contrast, it was only with great difficulty that Washington and Lafayette managed to persuade the dullard Rochambeau to join them in a joint campaign against Corwallis at Yorktown.
The most significant contribution that the French brought to the struggle was its fleet. The appearance of de Grasse' fleet at Yorktown sealed Cornwallis' fate, and led to the surrender of one-fourth of the British forces in North America.
