Actually the 310 silver dollars were struck in September and December of 1904 NOT 1905. As shown in the the "Annual Report of the Director of the Mint for the Fiscal Year Ended June 30, 1905" page #19.
Link to the report on the NNP
https://nnp.wustl.edu/library/book/514121 see the foot note at the bottom of the page, under the mintage charts.
Also

to CCF! The misleading thing with the Annual reports is the Fiscal Year which ends on June 30, each year. So it's not always easy to nail down an exact date from the reports, though in this case it isn't hard as there is a specific footnote relating to the extra 310 dollars and when they were minted.
You are correct they were cleaning up the left over silver bullion still on hand. On page #29 the 310 silver dollars coined in fiscal year 1905 (Sept. & Dec. 1904) came from Philadelphia also page #128 show Philadelphia coined all 310 silver dollars, so they were not San Francisco dollars as far as I can tell. Nothing states San Francisco as minting any silver dollars during the fiscal year of 1905. Page #76 shows NO silver dollars were struck as well.
"Buy the Book Before You Buy the Coin" - Aaron R. Feldman - "And read it" - Me 2013!
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