{"nrhp_refnum":"79000255","name":"Six-Inch Rifled Gun No. 9","other_names":["Six-Inch Disappearing Rifle"],"category":"object","location":{"address":"Baker Beach","address_restricted":false,"city":"San Francisco","county":"San Francisco","state":"CA","lat":37.793652370000075,"lon":-122.48254249599995,"geom_source":"nps_gis"},"listed_date":"1979-02-07","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Military"],"significance_levels":["state"],"summary":{"what_it_is":"A six-inch breechloading seacoast defense rifle (Gun No. 9, Model of 1905) on a Model of 1903 disappearing carriage, made at Watervliet Arsenal, Troy, New York (gun 1908, carriage 1903). It is mounted at Battery Chamberlin, Baker Beach, Fort Winfield Scott, San Francisco.","why_significant":"The nomination states it is one of only two such guns that survived the post-World War II scrapping of coastal defense ordnance. It is the only one of the two whose recoil mechanism still works, so it can move between firing and loading positions. It is argued to be nationally significant under Criterion C as a representative example of Endicott-period seacoast artillery.","narrative":"A six-inch steel rifle on a disappearing carriage sits in a concrete emplacement at Baker Beach in San Francisco. The gun tube was made at Watervliet Arsenal in 1908 and weighs 20,845 pounds. Its carriage, dating from 1903, uses lead counterweights to raise the gun over the parapet for firing, and recoil energy lowers it back behind concrete for loading. The gun first served at the U.S. Military Academy at West Point, where cadets fired it over the Hudson River and studied its parts. It escaped the scrapping of similar weapons, was later stored in Maryland, and was moved to San Francisco in 1976. It was installed at Battery Chamberlin in 1977. Only one other gun of this type survives, and this one has the operable recoil mechanism. It is recognized as a rare example of Endicott-era coast artillery, although the breechblock is missing and it cannot be fired.","period_of_significance":"1900-","architect_builder":"U.S. Army Watervliet Arsenal, Troy, New York","architectural_style":null,"criteria":["C"],"status_note":"Unaltered object, installed in February 1977 at Battery Chamberlin and maintained by park staff to control rust and keep the mechanism working. The breechblock is missing, so the gun cannot be fired.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:55:32.091673-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_CA/79000255.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/79000255/e72f19aa2e-800.webp","url_1600":"https://nationalhistoricalregister.com/media/79000255/e72f19aa2e-1600.webp","licence":"CC BY-SA 2.0","author":"Vards Uzvards","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Battery_Chamberlin_SF_CA.jpg\" rel=\"noopener\">Vards Uzvards</a>, <a href=\"https://creativecommons.org/licenses/by-sa/2.0\" rel=\"license noopener\">CC BY-SA 2.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Battery_Chamberlin_SF_CA.jpg"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/123861307","wikipedia":"https://en.wikipedia.org/wiki/Battery_Chamberlin","wikidata":"https://www.wikidata.org/wiki/Q4869826"},"indexable":true,"url":"https://nationalhistoricalregister.com/california/san-francisco/six-inch-rifled-gun-no-9-79000255/"}