Western Cartridge Co .45-70

I recently bought a 1973 mod Trapdoor Springfield. SN in 350,000 range should be about 1886 manufacture.

My question is.... my friend gave me some Western 45-70 GOVT. it doesn't have a box (a friend gave it to him) and he thought it might be for a lever gun.

All internet searches look like it's some antique Western Ammo. It's half copper jacket with a flat lead tip. It's crimped at the base of the bullet as well as at the top of the case. I don't have anymore info so I think I'm not gonna risk my new Trapdoor. But any input would be appreciated. I also have some brass for reloading and would like to do some light reloads just for fun shooting.

Thanks for looking at my post.

I am an amateur collector of military firearms.