Here's the bulk of what I have collected.
"The Pennsylvania Gazette
March 31, 1773
THO. PALMER Gun Smith. At his Shop, the North Side of Market street, between Fourth and Fifth streets, HAS for SALE, a Quantity of well made RIFLES , of different Lengths and Sizes of Bores, which he will insure to the Purchasers, to be as good and as handsomely fitted up as any made in America; he likewise makes Fowling Pieces, of different Sizes, such as have been approved of by Gentlemen of this City. All Persons that will please to favour him with their Custom, shall be served with great Dispatch and Care.
N.B. He repairs old Guns in the most careful Manner."
The original of the above ad, scroll down to Wed., July 6, 2016 and then a little more.
http://ofsortsforprovincials.blogspot.com/
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"The Pennsylvania Gazette
March 16, 1774
THO: PALMER Gun Smith AT his Shop, on the North Side of Market street, between Fourth and Fifth streets, hath for Sale, a Quantity of well made RIFLES, that he will dispose of very low for Cash. He likewise makes all Sorts of SHOT GUNS, such as straight Rifles, Cocking pieces, Fuzees, &c. in the best and neatest Manner, which hath gained the Approbation of some of the best Judges within the three Provinces. He also repairs old Work, in the most careful Manner. All Persons who will please to favour him with their Custom, may depend upon his Punctuality and Dispatch."
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"The Pennsylvania Gazette
March 6, 1776
EXTRAORDINARY Wages will be given to two or three Journeymen Gunsmiths, who are skilled in Stocking of Muskets and Rifles . Likewise good Encouragement will be given to a Gunlock Filer, that can make Musket Locks. --- Apply to THOMAS PALMER, the North Side of Market street, between Fourth and Fifth streets, Philadelphia.
N.B. Any person that has Skill to accomplish either of the aforesaid Branches, may, if they choose, work Piece work, and receive their Cash every Saturday Afternoon; or a Sum of Money will be advanced to them, by giving Security for the Delivery of their Work."
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A musket made by Thomas Palmer at Fifth and Market Streets, one of 40 ordered by Washington for the Prince William County Independent Company, a voluntary military organization in Virginia.
Museum of the American Revolution:
https://www.amrevmuseum.org/collection/thomas-palmer-musket
and
Spence