So as I understand it the Sepoys objected to pork and beef fat in the government ammo cartridges on a religious basis.
But to fight the British they logically needed ammo cartridges of some sort. How did they manage?
There's a slight fault in your question, as you'll see from the answer about to be linked. u/mikedash explores the matter of the cartridges in this post.
And, of course, more can always be said if others have more to contribute!