Armstrong guns were fitted widely in the RN, but they suffered a number of design weaknesses. During the bombardment of Kagoshima (Japan) in 1863 there were 28 accidents in the 365 rounds fired from 21 guns. On a number of occasions the vent pieces were blown from the guns. The guns were also inaccurate. This prompted the RN to reverting back to muzzle loading (ML) guns for the larger pieces. Another weakness of Armstrong guns was that there was nothing to prevent the gun being fired before the breech was closed. 
The offensive formation during the later part of the civil war transitioned based up the introduction of the rifled bore and is the focus of examination while simultaneously comparing the different weapons....
Breech Loading Rifled Artillery
The 12 inch guns fitted in HMS Dreadnought (1906) were the result of 20 years of development in breech loading (BL) main armament in the Royal Navy.
Small Arms and Ammunition - Essential Civil War …
HMS Colossus was destined to be the first British warship to be fitted with the new style RBLs, and I have taken this ship as the starting point of the story of the development of breech loading naval guns up to HMS Dreadnought.
Title: Small Arms and Ammunition ..
The French had stayed with RBL guns when the RN switched back to muzzle loaders, and two of their inventions stand out. The interrupted screw breech allowed a breech piece to be locked and unlocked by turning it through only a fraction of a circle, typically 30 degrees. This allows the breech to be swiftly opened and closed securely. The other was the de Bang obdurator – the mechanism that seals the rear of the powder chamber when the charge ignites. Without this seal, hot gasses would burn away the screw threads, and rapidly destroy the breech, and possibly injure the gun crew. The de Bang obdurator was significantly superior to the home-grown obdurators developed by the British arms manufacturers (e.g. the Elswick cup.)
produced wonderful effects in the Civil War, ..
The Greene was sold to Russia just prior to the outbreak of the Civil War, when it became the first bolt action rifle adopted by the US Ordnance Department, with a total of 900 pieces purchased.
Research Papers on Civil War Weapons ..
Alternatively, in his book Battle Tactics of the Civil War, Paddy Griffith compares the tactics used in the Civil War to those used during Napoleon’s time.