I desire; but so far the results with the 8-inch rifled and banded pieces have been most satisfactory. Your letter alludes chiefly to the 10-inch gun, but as your objections and conclusions must apply equally to the 8-inch as to the 10-inch, I must acquaint you that an 8-inch gun, rifled and double banded, in position at Fort Moultrie, has been fired through some four or five different engagements, in all over 100 times, with shell weighing over 100 pounds and bolts 140 pounds, with most satisfactory results, giving a greater range with the same charges and less elevation than the smooth-bore, with shell and shot of less than half the weight. The gun is uninjured, and there is no apparent reason why it should not last a long time.
It is regarded by General Ripley as the best gun in the battery, and in action has an immediate effect upon the enemy's iron-clads, which always try to avoid it.
This having proved a success, three others of the same kind have been prepared and placed in position in the harbor batteries, but owing to the limited supply of projectiles a thorough test has not been applied. The charges used have been 8 pounds and 10 pounds of coarse-grained powder, and the range shows these to have been sufficient to give full velocity to the projectiles for distances of 1,000 yards.
Experience shows that a large quantity of powder gives no increase of range, and with a rifled gun little additional velocity.
General Ripley, in one of his reports, makes the following statement:
The Brooke gun at Fort Sumter was fired with 15 pounds of powder at 18 degrees elevation, and although the charge was less than the maximum it finally cracked through the vent, and the gun was condemned. Happening to be present I ordered a reduction in using the remaining gun of the same kind, and better ranges were obtained with 10 pounds of mixed coarse-grained and common cannon powder.
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With 20 1/2 degrees a shell of 100 pounds was thrown 4 miles into the enemy's camp, and with 23 degrees it was thrown beyond Light-House Inlet and on Folly Island.
If the rifling and banding of the 8-inch and 10-inch columbiads is to be abandoned I consider it fortunate for Charleston that I have four of the former in position instead of the like number of smooth-bore 8-inch guns, which abundant experience here has demonstrated to be almost ineffective against iron-clads.
The experiment on 10-inch columbiads was first made with one which had a trunnion knocked off at Fort Sumter, and the rifling and banding of which was executed by a private firm. Another one was banded at the arsenal and rifled by the same parties who altered the first one. When finished I had the former mounted on Sullivan's Island and the latter on James Island. General Ripley writes as follows touching both:
They have both been tried, the latter a with a projectile invented by Captain Harding, weight about 215 pounds, and a Parrott projectile, weight about 250 pounds, and charges of 15 pounds and 16 pounds. With the latter excellent results were obtained. The former projectiles failed generally to take the grooves, and with 16 pounds broke up. The practice I have been informed has been delayed by the starting of one of the bands which was defectively welded, the gun itself being uninjured.
The other gun has been fired with 12 and 15 pounds of powder with Harding's projectiles only, others not having been furnished. Twelve hundred yards was
aOne at Fort Johnson, banded at the arsenal.