[Terry L Smith]

That is exactly correct!

A standard-issue ‘Brown Bess’ Tower flintlock rifle, using a 3/4 inch thick piece of English brown flint, igniting a powder charge sufficient to propel a 69-caliber lead ball to a target nominally 75 yards distant. The best musket men could load and fire THREE rounds per minute.

(Three rounds a minute was also the standard for the Union troops in the Civil War.)

[X Fretensis]

Believe Brown Bess fired a 75 cal. bullet. The French pattern Charlesville were 69 cal.

[Flick Lives]

Three rounds a minute was also the standard for the Union troops in the Civil War.

That's amazing. 20 seconds to clean the barrel, load in the gunpowder, wadding, shot, aim, and fire.