My guess would be Belgium made. Quality too high for India & sub-standard for England. The back-action lock, hammer and breech speak Belgium to me.
: Good find, bTW. Scrub the bore with 0000 wool and rapid-tap or WD 40 or something else like bore solvent.
: 1 turn in 100" is definitely for ball. you are lucky - if it was English, it might have a 36" twist too blood fast for heavy, brown-bear stomping loads.
:Have fun Cordite! I know I would.