Question

why were Indian unhappy with the new Enfield rifle

Answer 1

it was major feul to 1857

Answer 2

the Enfield rifle was the major fuel to 1857 rec Lt as it was rumored to have pork and cow fat and cartridges were supposed to be removed by mouth.
Hindus didn't eat cows and Muslims didn't eat pigs so it was unacceptable to all of them.
when mangal pandey revolted be was executed and then 1857 revolt began