I am getting a very good deal on a new Winchester 1885 in .223 and want to rechamber it to either a 225 Winchester or 220 Swift. Does the barrel have to be removed to do this? Is this a good idea or leave it as-is? What are the pitfalls to this project? The only good point in a 223 is less powder to be burned but the other 2 cartridges hold a lot of advantages. I do reload my own ammo.

Yes, the barrel will need to be removed to do the job correctly. You will also need a new (or modified) extractor for the larger case head. And, don't forget the 22-250...the most efficient of the lot.