Have had two experiences with "Classic" Winchesters that I could not get to shoot respectfully after trying everything I could think of, both rifle and loading wise.

Rifle 1 was / is a LH 338 WM.
Finely "noticed" that an extremely tight patch got tighter directly under the rear sight. A new barrel (Lilia) created a good shooting rifle.

Rifle 2 was a RH 300 ultra mag.
Could not find a smoking gun for it not being able to group less than 2" (Chamber was a little big around the shoulder and neck).
Bedding, re-crowning, trigger work, too much loading recipes and multi cussing never changed the results!
Re-barreling created a great shooting rifle.