One rifle only?
For where I live, my Ruger Ranch...older model that I apparently got lucky with since it is accurate for the model. While I am rural, there are few unobstructed vistas.
It as also never had a FTF in over 2k rounds.
One shotgun?
My Browning Citori O/U. I'm a simple man at the Citori is close to simple man proof.
One pistol?
Before I bought a Beretta 92D (DAO) two years ago, I would have written my Browning High-Power. I like 9mm for ease of use and recoil: My son has all the .45's except my Dad's Colt Commander from the early 50's.
The 92D is also almost simple man proof as well.
It is a theme with me