lets set the record straight. You took it to the gutter.
You imagined things that were not said or infered and then went on your inane rants about barrel burning and testing all cases, bullets and primers when YOU are the only one who took that there.
I point out one key flay in your stated technique as applies to your issue with barrel burning. Using one grain increments for testing increments will often result in skipping over a node and then you recommend a new barrel because of faulty testing methods ranks right up there for a "Heres your Sign award" and barrel burning for sure.
As for Federal primers being sensitive to pressure, I want to know where my pressure is and isn't and they are consistently produce accurate loads which helps when you want to be able to go past "acceptable hunting accuracy" into the zero realm.
I would recommend we drop this here, but if you must please explain "What is acceptable hunting load accuracy for a gun that shoots in the zeros? This I have to hear.
Suggest you take no more than two bullets and two powders for that cartridge whatever it is with seating depth set as I described before. Go to the range with loads for each starting loaded up to speed up the process. For example, 300 WSM
start with H4350 and MRP, 6mm BR use Varget and RL15. Pretty easy to ID the two common powders for any cartridge to start with. Most cartridges have 2-3 major and most common "go to" powders.
Shoot your loads (ladder or 2-3 shot groups, you pick)and then tweak the powder loads while at the range , then seating depth last. IF you have a chrono and SD/ES is an issue, try different primers.
Contrary to some opinions, primer changes can radically open a group up (up to 1" or more) particularily when going from a regular to a magnum primer and vice versa. they can also take a good working load and really tighten it up that last final bit.