Innovation continued well into the next century. Boss o/u for a start; not that superimposed barrels were anything new, but the way they were put together to combine the same features KY Jon above indicates and in a very much more refined way than previously, surely was innovative. Look at the many patents issued by best gun makers like Woodward, Beesley, H&H, Lancaster as examples of their minds still coming up with ideas and refinements.
Purdey's carried on refining their guns too. They have always acknowledged Beesley's patent of 1881 as being the bedrock of their subsequent guns. So many satisfied customers probably indicated to them that the design was right so why change it too much.
The petrol engine is still essentially the same design as Herr Benz drew it in 1879. It too has had innovative refinements along the way. I'm not sure I'd call that technological stagnation.
Tim
