The Armstrong was here in very limited numbers,Kymm. Only two, that I have been able to determine, were released to the South by the British Government. Federal Minister Adams placed the release of the Armstrong in the same category as the release to the Confederacy of the turreted cruisers Wyvern and Scorpion in correspondence to Lord Palmerston.
This correspondence threatened sanctions leading to open warfare if those weapons were allowed to the Confederacy.

Search H.M.S. Warrior for references of the Armstrong breechloader as an naval arm.
This ship has survived as artifact and still maintains her compliment of Armstrongs.

The Armstrong had breech sealing problems. Blowby of gases increasing with erosion of affected parts. A first-generation effort. Folks might nay-say the previous statement. How many of the earlier breech loaders had hinges?