The gun-barrel CH'ON-JA-CH'ONG-T'ONG was the largest cannon in a series of the barrel type firearms used from the earliest period of the Choson dynasty era. Specifications, including the ranges of the iron cannon ball and Large General-Arrow fired from the gun-barrel, are found in old documents and the ranges of the Large General-Arrow specified in the weapons manual Yungwon P'ilbi (1813) correspond to the distances of 1,134 m and 1,512 m after unit conversion. In the present report, the trajectories of the Large General-Arrow fired from CH'ON-JA-CH'ONG-T'ONG have been evaluated for each gun elevation by use of the computer code "Projectile Design and Analysis System". The 32-kg Large General-Arrow with the full length of 2.77 m and the diameter of 12 cm was assumed to be fired with 1.16 kg gunpowder. The calculation for the maximum range yields 786 m at 44° elevation. Calculated trajectories for each elevation are graphically represented and also tabulated to show the flight data. Then, the effective gun range, i.e., the point blank shot, is estimated to be about 70 m which seems quite perceptible in the context of the successful outcomes at sea battles demonstrated by Admiral Yi Sun-Sin's iron-clad turtle-boats in 1592.