Francis William O'Connell 1863

Hi everyone, i have been trying to find more information on my g.g.g.grandfather Francis William O'Connell. He was baptised in 1863 in Buttevant County Cork by father J.Lynch. He was a roman catholic and his parents were William O'Connell (military man, private 2nd battalion 18th company) and Ann Harford. I am unsure of when he left Ireland but he married in New Zealand in 1884. I do not know why he left or if he was the only member of his family to travel abroad. I would very much appreciate any information anyone can give me.

Many thanks,

Shirin