I cant say I've ever found a bullet like this before. Is it pulled and a piece of the puller broke off in it? I'm lost lol. Thanks for your help folks!
What is the caliber and weight to go further? Winchester made at one time what they called an express bullet, with a covered copper tube in the front. Kind of a covered hollow point.
It is definitely a .577 Snider-Enfield bullet, from the late-1860s into the early-1870s. The Snider-Enfield rifles and bullets are known to have been issued to Canadian Northwest Mounted Police. It was manufactured with the small iron plug in its nose.
Although your Snider-Enfield bullet resembles an American civil war "Minie-bullet," unlike that type it has 4 body-grooves and it is absolutely from after 1865.