I did a quick Google on it, here's a link to another forum where a guy is trying to figure out what size buckshot they used and cites several Revolutionary archaeological digs that recovered buck and ball loads.
Here's some pretty good validation from the Springfield Armory museum that gives a brief history of the '41 Springfield musket. It has a paragraph about buck and ball that refers to it being used in the Revolution. That first sentence fragment is their typo.
http://ww2.rediscov.com/spring/VFPC...g/DETAILS.IDC,SPECIFIC=9828,DATABASE=objects,
Although loading a single-round ball seems to have been stanAlthough Champlain used full-sized balls, by the time of the American Revolution it was common practice to load smaller buckshot, averaging around .30-caliber, along with a musket ball in the paper cartridges used in .69 and .75-caliber muskets. The number of buckshot per cartridge varied, and, in the 1775 attack on Quebec, General Henry Dearborn carried a musket 'charged with a ball and Ten Buckshott.' In October of 1777, General George Washington recommended that his men deliver their first volley with a load of 'one musket ball and four or eight buckshott, according to the strength of their pieces.' In October 1777, Washington ordered that 'buckshott are to be put in all cartridges which shall hereafter be made.' Some Revolutionary War cartridges were purchased from contractors, while others were made up by the soldiers themselves. Maryland issued troops bullet molds casting both buckshot and musket balls.
Single-ball, buckshot-and-ball, and straight buckshot loads of from twelve to fifteen pellets remained part of the American military ammunition inventory after the Revolution. Those men on the Lewis and Clark expedition who carried muskets were issued one hundred balls and two pounds of buckshot each and cartridges loaded with both buckshot and ball were standard issue during the War of 1812. Single-ball loads for the .69 caliber United States musket fired undersized .64-caliber projectiles to facilitate quick loading, at the expense of accuracy. The addition of buckshot made a hit more likely.
here's a link to another forum where a guy is trying to figure out what size buckshot they used and cites several Revolutionary archaeological digs that recovered buck and ball loads. He also mentions Washington's orders for buck and ball to be used.
http://forums.gunboards.com/showthread.php?64021-Rev.-War-Buck-n-Ball-loads
The majority of excavated shot displayed from our Ft. Clinton, lost and destroyed by the British in Oct. 1777, are clearly larger than .25 and appear to average in the low .30’s
Thomas’ three-volume tome, Round Ball to Rimfire, demonstrates pre-Civil War buckshot as .30 from the Hudson Highlands in 1781 as well as
a packet of ten cartridges possibly of Rev. War vintage where the buckshot in the one removed for testing shows to be greater than .25 next to the .69 caliber ball they sit atop.
A curator at the West Point Museum shared that they have two known-to-be Rev. War buck-n-ball cartridges there and the x-rayed buckshot is .32 diameter.
The Heidelberg College excavation of the 1795 Fallen Timber Battlefield found three .25 pellets vs. 35 .31 pellets.