Moving on...
The sources cited by Carl P. Russel for his quotes are...
Treatise on the Rifle, Musket, Pistol & fowling piece, embracing projectiles & sharp shooting, Also The Manufacture Of Guns, And The Preparation Of The Materials Suited To Their Construction. A New Armament Proposed-More Efficent, Ornamental, And Less Weight. By N. Bosworth, civil & military engineer.1846
and Woodburne Potter's...
The War in Florida. 1836
Potter was there, Bosworth was citing after the fact. Both are apparently still available in print and I hope to have them in hand shortly.
Guys like me merely read the stuff that REAL Historians wrote, and extraordinary amount of correspondence and writing occurred within the year of 1836 pertaining to the events of that year in Florida. As best I can gather at short notice, Winfield Scott, who simply hated Edmund Gaines, had a Senate inquiry brought that same year.
Some idea of the labors wrought by REAL Historians can be had by perusing the records anf testimony of that lengthy hearing....
Public Documents Printed by Order of the Senate of the United States. 1836
Though dreadfully long, the pdf is searchable. Searching on "Izard" will quickly bring you to the testimony.
Unfortunately this does not include Gaines' original report pertaining to the battle.
One can readily determine however that the Seminoles and Black Seminoles were commonly armed with rifles.
Also, making some issues moot, turns out there were a considerable numbers of rifle-armed civilian volunteers in Gaines' force on the Withlacootchie.
Again, unfortunately not the original report, a letter from Gaines himself, sent on July 4th of 1836. Here's an excerpt. I'm liking this guy better and better....
American Historical Magazine. 1900. Skip to page 145 for Gaines' letter.
It may be said that I did not expose my officers and soldiers volunteers and regulars to as much risk and loss as some my accusers deem necessary to give éclat to a triumph. Heaven preserve me I pray from that éclat which is won by the useless or wanton sacrifice of those placed under my command.
Some indication thus far that Gaines' original report to Secretary of War Lewis Cass may be held at Duke University.
I'll report back when I have it.
Birdwatcher