Several messages were received about Steampunk guns.
Most regarding "popularity". Or, where to begin.
I'm responding with a forum thread and group blog.
There are several photographs of Steampunk guns in the 2015 and 2016 photo galleries.
This is a loose definition, and a personal interpretation reflecting my interaction with the people who make and share their skills and art. But, let's not forget "Steampunk" is about having fun.
Many Steamer's prefer historically accurate weapons, where style and function are correct for 19th Century reenactment. However, some adventurers require more exotic devices, commonly called rays guns. These weapons fire beams of channeled and destructive energy. Even personalized rail-guns have manifested into the CONS; weapons utilizing electromagnetic forces to achieve a very high kinetic energy of a projectile. I confess, my personal favorite(s) arms are the hybridized and individualized CIWS /Phalanx; better known as Gatling Guns. The Steampunk variant is not "hand-crank" operated, or dependent on some "newfangled-nonsense" called electricity . As you might guess, steam powered barrels release a destructive maelstrom on your enemy.
~R.