Hard Chrome will give you best durabilty of any common finish on the market. However, it is kind of bright if it's a hunting rifle. A lot of people will use a camo sleeve for bright guns when hunting or you can have it re-finished with one of the resin based finishes. They come in a variety of colors and are usually cost effective. Some are durable or rustproof or both. Surface blemishes on the metal are removed as part of the process. (But not rust pitting) If I had to pick a good shop for a resin based finish, I would suggest uhmm..well...hmmm..lets see...Ahaa!
Mac's Shootin' Irons in Tucson. Guranteed rust proof in writing. Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
http://www.shootiniron.com