Did Sherlock Holmes use a gun?

Answer 1

He was known to use a gun on occasion. Normally he let Watson do the gun work. Holmes decorated the wall of their flat in 221B Baker Street with a VR in honour of Queen Victoria (Victoria Regina) that he shot into the wall.

In The Sign of the Four, Holmes and Watson both fired at the dwarf and one or the other of them hit and caused him to die.

In the most famous of the Holmes stories, The Hound of the Baskervilles, Holmes and Watson both fired at the hound and one or the other hit it, but Holmes outran Watson and killed off the giant dog by emptying "five barrels of his revolver" into it at close range.