Things you may know already:

http://www.harpweek.com/09Cartoon/BrowseByDateCartoon-Large.asp?Month=July&Date=24

I checked eBay. There are a couple of seller with the bound year, 1875, for Harper's Weekly as well as at least 1 selling this particular issue.

http://www.lrml.org/historical/creedmoor/hw18741010.htm

http://www.researchpress.co.uk/targets/creedmoor/index.htm

Interesting that the photograph is not the same as the print in Harper's. Rockwood must have taken a series of photo's at the event. I would not be surprised if he did individual portraits of the competitors with their rifles. This was a common subject for 19th century photographs. Certainly he would had done it so he could sell the images later from his shop. People would visit photographers saloon's to collect such images to display at home or place in their family album.

The GEH database contains the following information. While it lists institutional holders, it not does have information regarding which photos they hold.
Quote:

HOLDERS OF Rockwood, G.G. by State
------------------ MODEST holdings except # (SUBSTANTIAL) ------------------
1 #NY Rochester George Eastman House
2 CA Los Angeles J. Paul Getty Museum
3 CT Hartford Harriet Beecher Stowe Center
4 CT Mystic Mystic Seaport Museum
5 CT New Haven Yale University Art Gallery
6 DC Washington National Museum of American History
7 DC Washington National Museum of American History (Graphic Arts)
8 DC Washington National Portrait Gallery
9 GA Athens Hargrett Rare Book and Manuscript Library
10 MA Boston Boston Athenaeum
11 MA Boston Boston Public Library
12 MA Boston Massachusetts Historical Society
13 MA Boston Society for the Preservation of New England Antiquitie
14 MA Lowell Center for Lowell History
15 MA Northampton Smith College Museum of Art
16 MD Baltimore Albin O. Kuhn Library & Gallery
17 MI Dearborn Henry Ford Museum & Greenfield Village
18 MO Columbia State Historical Society of Missouri
19 MO Kansas City Hallmark Photographic Collection
20 MT Helena Montana Historical Society
21 NM Santa Fe Museum of New Mexico - Photographic Archives
22 NY New York Metropolitan Museum of Art (Dept. of Photographs)
23 NY New York Museum of Modern Art
24 NY New York New York Public Library
25 NY Rochester Visual Studies Workshop
26 NY Staten Island Staten Island Institute of Arts & Sciences
27 NY Tarrytown Historical Society of the Tarrytowns, Inc.
28 NY Utica Oneida County Historical Society
29 PA Philadelphia Library Company of Philadelphia
30 SC Charleston South Carolina Historical Society
31 SC Columbia South Caroliniana Library
32 TX Austin Harry Ransom Humanities Research Center
33 VT Woodstock Woodstock Historical Society, Inc.
34 Amsterdam Rijksmuseum, Amsterdam
35 Montréal Canadian Centre for Architecture
36 Ottawa National Gallery of Canada

BIBLIOGRAPHIC CITATIONS FOR Rockwood, G.G. ------------------

1 See card catalog for title(s) in GEH library.
2 Parry, 1979 REFERENCE BOOK Photography Index: A Guide to Reproductions
3 Rockwood, G.G. 1865 ARTICLE Philadelphia Photographer
4 Welling, W. 1978 MONOGRAPH Photography in America: The Formative Years, 1839-1900
5 Wilson, J.G. 1901 BOOK Appletons' Cyclopaedia of American Biography

EXHIBITS CHRONOLOGY FOR Rockwood, G.G. --------------------

1 1865.09.15 Thirty-sixth Annual Fair of the American Institute
American Institute of the Cit B
2 1867.11 Great Exhibition of the American Institute (Thirty-seventh ?)
American Institute of the Cit B
3 1869.10.00 Thirty-eighth Annual Fair of the American Institute of the City
Empire Rink B
4 1870.10.00 Thirty-ninth Annual Fair of the American Institute of the City
Empire Rink B
5 1871.09.07 Fortieth Annual Fair of the American Institute of the City of N
American Institute of the Cit B
6 1872.10.00 Forty-first Annual Fair of the American Institute of the City o
American Institute of the Cit B
7 1873.10.00 Forty-second Annual Fair of the American Institute of the City
American Institute of the Cit B
8 1884.10 Fifty-Third Annual Fair of the American Institute of the City o
American Institute of the Cit Rich, Theodore D. B
9 1884.12.16 World's Industrial and Cotton Centennial Exposition of New Orle
United States of America B
10 1885.10 Fifty-Fourth Annual Fair of the American Institute of the City
American Institute of the Cit Dean, William B
11 1888.07.10 Ninth Annual Photographers Association of America Convention Ex
Photographers Association of Hays, B.S. B
12 1888.10 Fifty-Seventh Annual Fair of the American Institute of the City
American Institute of the Cit Dean, William B
13 1889.10 Fifty-Eighth Annual Fair of the American Institute of the City
American Institute of the Cit Laudy, L.H. B
14 1890 American Institute Fair B
15 1892 American Institute Fair
American Institute of the City B



Pete