Frankford Arsenal The Frankford Arsenal was a United States Army ammunition plant located adjacent to the Bridesburg neighborhood of Northeast Philadelphia , Pennsylvania , north of the original course of Frankford Creek . History . Opened in 1816 on 8 . 1ha ( 20 acres ) of land purchased by President James Madison , it was the center of U . S . military small - arms ammunition design and development until its closure in 1977 . Among the many other products manufactured at the arsenal were fire - control and range - finding instruments , and gauges for these components . With the outbreak of the Civil War , the arsenal ' s commander , Josiah Gorgas , resigned and joined the Confederate States Army in deference to the wishes of his Alabama - born wife and reporting to the Confederate capital in Richmond with a large supply of U . S . Army guns and ammunition . By the end of the war , the arsenal employed over 1 , 000 workers . It served as a major site for the storage of weapons and artillery pieces , a depot for the repair of artillery , cavalry and infantry equipment , repair and cleaning of small arms and harnesses , the manufacture of percussion powder and Minié ball s , and the testing of new forms of gunpowder and time fuses . During the Gettysburg Campaign , the arsenal provided tens of thousands of musket s and vast supplies of ammunition for Pennsylvania ' s " Emergency Militia " regiments . Among the innovations extensively tested at the Arsenal was the Gatling Gun , an early form of machine gun that saw extensive service in the Indian Wars . During World War I and World War II , the arsenal was again busy with supplying the war efforts , providing a major source of jobs and income for the region . At times , employment reached 22 , 000 . The Frankford Arsenal was an entity unto itself , a virtual city within a city , and contained everything from its own police and fire departments , Buildings and Grounds , dining halls , as well as everything from maintenance and motor pool , to a complete medical facility . The Arsenal was part of the U . S . Arsenal System - dedicated military establishments spread throughout the country to perform specific military missions for the Government . From the beginning , the Frankford Arsenal was involved in the design and manufacture of munitions . As military weapons became more complex , the Center ' s role expanded to cover the development of a whole range of the Army ' s more advanced weapon systems . The Arsenal contained the world - famous Pitman - Dunn Laboratories along with a number of other R & D departments . Arsenal scientists and engineers designed and developed everything from basic materials to LASER guided ballistics , all produced entirely in - house from the concept phase to the fielding of the equipment . New portable and imbedded computer applications saw the development of the LASER rangefinder , fielded artillery computational machines ( FADAC ) and radar systems . During the Vietnam War , experiments in caseless ammunition , far - infrared low - light - level technologies , and advanced LASER applications were under development . The labs were supported by a full range of first - class drafting and machine shops scattered throughout the many buildings of the Center . Everything from milling , to electroplating , to multi - layer printed circuit board fabrication could be accomplished by “ The Shops ” . The Optical Lens Design Facility was one of the finest in the country . The Optical Assembly shop also refurbished field binoculars . Once a newly designed system was manufactured , complete structural and environmental testing was necessary to insure that the device could withstand the rigors of a fielded environment . This was accomplished in the Arsenal ’ s environmental testing and evaluation facility . As the U . S . military - industrial complex grew , the Arsenal could no longer compete as a manufacturing entity . More and more of its programs were farmed out to industry . The Arsenal ’ s functions were eventually transferred to the Picatinny Arsenal in New Jersey . During the presidential campaign of 1976 , Walter Mondale stood in front of the Frankford Arsenal and promised that it would remain open . The Carter / Mondale ticket won the election but the promise was not fulfilled ; the arsenal closed for U . S . government use in 1977 . Before closing , many custom designs were developed and tested , including the use of aluminum and steel for the manufacture of cartridge cases . The northernmost part of the site was assumed by the Pennsylvania Fish and Boat Commission for use as a boat ramp and fishing spot on the Delaware River . The southernmost part is currently being used as a light - industrial and office park . Munition markings . Each round of ammunition was marked with the headstamp " F A " on its base , denoting that it was produced at the Frankford Arsenal . Early metallic cartridges produced at Frankford were not head - stamped . These were either Martin or Benet primed copper cases . Early cartridges were stamped " F " for Frankford or " R " for rifle or " C " for carbine . Ammunition produced prior to WW I was dated with the numerical month - year headstamp , such as " 8 79 " or " 2 12 " , indicating August 1879 or February 1912 as date of manufacture . Match - grade 7 . 62 mm ( . 308 ) cartridge cases were manufactured in limited quantities . Cartridges conforming to NATO specifications were marked with the NATO cross ( a circle containing a " + " ) .