Bonanza,

Hartman and Co was the name of an illustrious British firm that existed in Calcutta until 1947 when the British left. Unlike Manton, Rodda and Daw which survived in name, the Hartman business died with the British Raj. If this is a Hartman from India, then you have a rifle with an amazing history and possibly more than a few tigers to its credit from the heyday of the British empire.

Beautiful rifle, most importantly, and congratulations! Hope to see some nice hunt pics in the future featuring your new acquisition!