The 7-inch RML gun was developed in  1865 to replace the 7-inch RBL gun which had fallen out of favour.  The first two marks of this gun were produced by the Armstrong production method, but from the Mark III onwards a cheaper Woolwich design was used.  The variants produced:

  • 7 tons, Mark I to Mark IV
  • 6.5 tons, Mark I to III
  • 90cwt gun