<P> During the Civil War, the armory became a site of great strategic importance because it was located very close to the Mason - Dixon line, or the border between the free and the slave - holding states . Consequently, the Union used it as an effective means to supply troops with weapons quickly as they marched into battle . The downside to being on the border was that the armory could easily change hands and fall into Confederate control - the town of Harpers Ferry changed hands at least eleven times during the Civil War . </P> <P> After the Civil War, John Brown's Fort was the only building to survive the destruction wrought upon it by the Confederates and the Union . The building was named after John Brown for his notorious raid on the Harpers Ferry Armory in 1859 . The building was the armory's fire engine and guard house . Due to the degree of damage to the armory during the Civil War, the U.S. government decided not to re-establish the armory at Harpers Ferry, instead focusing the quickly developing areas west of the Mississippi River . </P> <P> Today the site is mostly covered by railroad track embankments . </P>

Why was the production of breechloading rifles revolutionary at the harpers ferry armory