Robert Taylor Pritchett was a gun manufacturer, artist and illustrator. As artist he painted royal ceremonies for Queen Victoria, and he illustrated Darwin's The Voyage of the Beagle.
R. T. Pritchett
"Baptism of Princess Victoria Eugenie of Battenberg at the drawing room of Balmoral Castle" (1887)
"Homeward Bound", from The Voyage of the Beagle (1890)
Rifling is the term for helical grooves machined into the internal surface of a firearm's barrel for imparting a spin to the fired projectile to improve its aerodynamic stability and accuracy. It is a
Rifling of a 105 mm Royal Ordnance L7 tank gun
Conventional rifling of a 90 mm M75 cannon (production year 1891, Austria-Hungary)
Rifling in a GAU-8 autocannon
Traditional rifling of a 9 mm handgun barrel