- Author
- A.N. Other and NHSA Webmaster
- Subjects
- None noted
- Tags
- None noted.
- RAN Ships
- None noted.
- Publication
- June 1981 edition of the Naval Historical Review (all rights reserved)
Another objection was that the vent had to be lifted right out of the breech, and the copper sealing ring was easily damaged. The rate of fire was not as fast as the old ‘down the spout’ method. But notwithstanding these faults the system showed promise.
Looking back it is hard to understand just why such haste was made to adopt the screw breech without conclusive trials. The first trial was carried out in January 1859, when a gun with a 4.75-inch bore, firing a 35-pound projectile and using a 6-pound charge, was fired at an old floating battery named Trusty. A total of fourteen rounds were fired at very short range, starting at 450 yards and ending up at 50 yards. It was quite evident that the gun was a failure, but in their wisdom the Board of Ordnance decided that the projectile weight should be increased to 40 pounds and the charge reduced to 5 pounds. The service designation of RBL 40-pounder, Armstrong, was thus given to a less powerful one that had failed.
A second series of tests were carried out in September 1859, but this time using a 6- inch gun. Projectiles of varying weights from 100 pounds down to 78 pounds were tried out. A fine performance was expected from this gun and the trials were to be the reverse of the original, in this case the first shot would be fired at 400 yards and the range then opened. The reverse took place. The experimental gun performed more miserably than the 40-pounder.
Despite these failures the project went ahead, thousands of guns of various calibres were ordered for both seas and land service, but in the long run defeat had to be admitted.
To salvage the project, a modification was made to the breech. A new type was brought out, this one having the vent piece entered from the side, but although the projectile and charge were still entered through the breech, in the side vented model the vent piece, now called a ‘stopper’, was held in place by an expanding wedge. This system was far worse than the original, and soon disappeared from use.
To gain an idea of the short-lived screw breech gun, one has only to peruse the armament of HMS Warrior, the first iron clad. When completed in October 1861, the ship was armed with a mixed battery of twenty-six 68-pounder smooth bores, ten 110-pounder RBL and four 70-pounder RBLs. In 1867 we find that she was re-armed with four 8-inch RML (rifled muzzle loading), twenty-eight 7-inch RML and four 20-pounder RBL. In this case the breech loaders were carried as saluting guns only.
The gunnery captain of HMS Cambridge was far from happy with the Armstrong gun, and his words summed up the situation very nicely when he said that all of them that he had seen had flaws, and added ‘It will be a long time before it bursts, but a gunner does not like to stand alongside a gun with a few cracks in it.’
Put under actual service conditions the gun proved very bad indeed, as was amply demonstrated at the Bombardment of Kagoshima, Japan on 14th August 1863. One observer stated that the guns threw their projectiles anywhere other than where they were aimed, and many others reported on their erratic shooting. But a more serious defect was the number of accidents experienced, the Armstrongs ended up with an average of one accident for every 13 rounds fired. This of course was certainly not good enough, and very shortly the screw breech gun was withdrawn from general use.
A retrograde step was made by reverting back to the rifled muzzle loading system, as efficient breech loading systems were available in Europe. In France, the de Bange system was working, and working well. So well that it was eventually adopted into the British service, but not before the ELSWICK cup obturation system had been issued. But that is another story.
The net result of the reversion to the RML system was that British gunners had to put up with the back-breaking task of getting heavy shells into the muzzles of their guns for another twenty years. It is quite on the cards that had HMS Thunderer not suffered her unfortunate explosion which killed 11 men and injured 30 others in January 1879, the RML system would have lasted a lot longer. In the case of the gun explosion in Thunderer, one gun in the turret misfired, and another charge and projectile were loaded. The double charged and shotted gun blew up on the next attempt, but it was quite obvious that such an accident would be impossible with breech-loaders.
When breech loading was again introduced, the old screw breech passed into history.