could anyone advise of the process/cost to convert a 1889 86 to .50 express..the rifle was previously converted to .33 winchester....any directions or thoughts regarding this would be greatly appreciated

i assume you are NOT meaning the 50 AE ..

here's a thread I found for you
https://www.shootersforum.com/...ter-50-express.3912/

i'm doing one.... change the barrel... bolt face is the same... doubt there'll be any feeding issues...