Question: What river is the weapons manufacturer that developed the M15 pistol located on?

Context paragraphs:
Ares Incorporated: ARES Incorporated is an American weapons manufacturer and firearms engineering company co-founded by the American weapons inventor and developer Eugene Stoner in 1971.  The company is based in Port Clinton, Ohio, and produces fire control systems, turret systems, small arms, automatic cannons and industrial machinery.  Mr. Stoner left the company in 1989, joining Knight's Armament Company in 1990, where his designs included the "Stoner 96", a further refinement of the ARES LMG/Stoner 63.

9×19mm Parabellum: The 9×19mm Parabellum, also known as 9 mm Luger by the C.I.P. or 9 mm NATO by NATO (abbreviated 9mm, 9mmP, 9×19mm or 9×19) is a cartridge that was designed by Georg Luger and introduced in 1902 by the German weapons manufacturer Deutsche Waffen und Munitionsfabriken (DWM) (German Weapons and Munitions Factory) for their Luger semi-automatic pistol.

M15 pistol: The M15 General Officers is a .45 ACP pistol developed by the U.S. Army's Rock Island Arsenal from stock M1911 pistols as a replacement for the aging Colt Model 1903 and Model 1908 Pocket Hammerless pistols.  The pistol was issued to United States Army general officers as a personal weapon.

Rock Island Arsenal: The Rock Island Arsenal comprises 946 acres , located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois.  It lies within the state of Illinois.  It is home of First Army headquarters.  The island was originally established as a government site in 1816, with the building of Fort Armstrong.  It is now the largest government-owned weapons manufacturing arsenal in the United States.  It has manufactured military equipment and ordnance since the 1880s.  In 1919–1920 one hundred of the Anglo-American or Liberty Mark VIII tanks were manufactured, although too late for World War I.  It is designated as a National Historic Landmark.

Carbon 15: The Carbon 15 is a family of lightweight, magazine-fed pistols, carbines, and rifles developed by defunct United States weapons manufacturer Professional Ordnance, with the design picked up after some time by current manufacturer Bushmaster Firearms.

Pier 11/Wall Street: Pier 11/Wall Street is a pier providing slips to ferries and excursion boats on the East River in the Port of New York and New Jersey.  It is located east of South Street and FDR Drive just south of Wall Street in Lower Manhattan, New York City.  The ferry terminal has five landings (A, B, C, D, E), each with two berths, and is used by four privately owned companies.  Within walking distance, public transportation includes the New York City Subway's trains at South Ferry – Whitehall Street and trains trains at Wall Street; the M55, M15, M15 SBS, M20 New York City Bus routes, and the Staten Island Ferry.

Israel Military Industries: IMI Systems, formerly Israel Military Industries, also referred to as Ta'as (Hebrew: תע"ש מערכות ,התעשייה הצבאית‎ ‎ ), is an Israeli weapons manufacturer.  It manufactures weapons, munitions and military technology mainly for Israeli security forces.  (especially Israel's army, the Israel Defense Forces or IDF)

Tula Arms Plant: Tula Arms Plant (or Tulsky Oruzheiny Zavod, Russian: "Тульский оружейный завод") is a Russian weapons manufacturer founded by Tsar Peter I of Russia in 1712 in Tula, Tula Oblast as Tula Arsenal.  Throughout its history, it has produced weapons for the Russian state.  Its name was changed from Tula Arsenal to Tula Arms Plant during the Soviet era.

Python (missile): The Rafael Python is a family of air-to-air missiles (AAMs) built by the Israeli weapons manufacturer Rafael Advanced Defense Systems, formerly RAFAEL Armament Development Authority.  Originally starting with the "Shafrir" (Hebrew: שפריר‎ ‎ , loosely translated as Dragonfly, a male form of inflection for Damselfly (שפרירית)) series, the "Shafrir-1" missile was developed in 1959, followed by the "Shafrir-2" in early 1970s.  Subsequently, the missiles were given the western name of ""Python"" by the parent company for export purposes, starting with the "Python-3" in 1978.  Since then, it has been further developed and evolved into the "Python-4", "Python-5", "Derby" and also, the SPYDER, an advanced ground-based air-defence system.  Currently, the missiles are in service with the armed forces of over fifteen countries from around the world.

Astra 400: The Astra modelo 400 was a Spanish service pistol produced by weapons manufacturer Astra-Unceta y Cia SA.  as a replacement for the Campo-Giro 1913/1916, which had also been chambered in 9mm Largo.  It was the standard issue sidearm in the Spanish Army during the Spanish Civil War and also saw service in Germany during World War II.

Supporting paragraphs: M15 pistol Rock Island Arsenal
Answer: Mississippi River