What is the history of the 13 B Army Cannoneer (Cannon Crewmember), and how does that relate to what they do now?

They still move load and fire the cannon. The job is 100% manual labor for E1-E4. Once making E-5 and E-6 you're still on the cannon doing less manual work about 75-25% manual work. This is the Army's version of ditch digging. This from my experience being a 13B and 13A (Field Artillery Officer).

the Old Crew is not too much different just the advancements in Technology and Industry has brought the Cannon Cockers into the 21st century ... its Just an Occupation moving into the next Stages of Life

Improved mobility and automatic triangulation. They are able to keep up with Armor and Infantry to a degree. The accuracy and range improved dramatically.