Ok, then it’s the case sticking in the chamber. Your bolt head and barrel chamber all look fine from the picks. Maybe little dirty or just normal haze from age. You could try polishing the chamber as Jim suggested. Also, there are a couple things you can do for a mechanical advantage in lifting the bolt/primary extraction. A longer bolt handle/knob, and also a lift kit. Many of us already have these done on our rifles. There is also some bolt polishing, firing pin tweaking, but these should not be done unless one knows what they are doing. But the bolt handle & lift kit are easy tricks and worth a try.