Good reference books. There are many indeed but if you are a rifle guy and a hunter, here are two you should round up:
Optics for the Hunter – John Barsness: This book is the de facto reference guide for everything optics when it comes to hunting. A bit dated and out of print but the basic principles still apply. Check Amazon.
Rifle Bullets for the Hunter – John Barsness, Craig Boddington, John Haviland, Richard Mann, Ron Spomer & Bryce Towsley: Everything you always wanted to know about rifle bullets but did not know who or were afraid to ask. This is a first of its kind book about hunting bullets and everything from varmint bullets to solids are covered. I only have two copies left for sale ($ 40.00) but you might be able to find one used somewhere. Amazon lists two starting at $ 69.