Report of the Joint Committee on the Conduct of the War : at the second session Thirty-eighth Congress . times, and was much en-larged, giving a windage of more than three-tenths of an inch over the shot, and therebycausing ureat loss of velocity and rtnge. Ihe initial velocity of the shot fired with 1? pounds of powder was determined by meansof the Viswotte chronoscupe when the gun had 130 rounds. The velocity thus obtainedwas 1,480 feet Owing to the difficulty experienced from the fragments of the lead thrown from the shotcutting the wires prematurely, no efforts were made subsequently to ob
Report of the Joint Committee on the Conduct of the War : at the second session Thirty-eighth Congress . times, and was much en-larged, giving a windage of more than three-tenths of an inch over the shot, and therebycausing ureat loss of velocity and rtnge. Ihe initial velocity of the shot fired with 1? pounds of powder was determined by meansof the Viswotte chronoscupe when the gun had 130 rounds. The velocity thus obtainedwas 1,480 feet Owing to the difficulty experienced from the fragments of the lead thrown from the shotcutting the wires prematurely, no efforts were made subsequently to obtain the velocitieswith other charges. The greatest enlargement of the bore of the piece for the first 100 rounds was onehundred and twenty-one-thousandths (0 1^1) of an inch, aud at fifteen (15) inches fromthe bottom. After this the enlargement wa- slight for each additi(jnal one hundied (100)rounds, until we had reached five hundred (500) rounds, and began to use twenty-five(25) pound charges. After the six hundredth (600) round the enlargement exceeded three-tenths of an inch, 148 HEAVY HEAVY OEDNANCE. 149 which is the greatest measurement the star-gauge would record ; this maximum enlarge-ment extended for a distance of three (3) inches along the bore, beginning at a point 20inches from the bottom. When the triils commenced the vent was in the metal of the gun, there being no vent-piece, and was so much enlarged by the first 100 rounds that it had to be bouched ; a cop-per vent-piece secured by a steel plug screwed in was inserted, and answered for the restof the firing. At about the 560th round it was first discovered that the metal of the gun had been somuch stretched laterally at the place of maximum interior enlargement that it was plainlyvisible in a swell on the outside entirely encircling the piece. There was an increase of \of an inch in the exterior diameter at that place. This swell gradually diminished tonothing at a distance of 4 inches on either side
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgettysb, bookyear1865
