Whats causing these bad groups?

Ive got a 280ai in the savage ultralite that im about to pull my hair out over. I cant get it to groups consistently. It either shoots 1/2moa or 2moa (pic attached)
The gun has approximately 300 rounds through it and heres what ive tried.

- 4 types of powder, 3 types of bullets, 2 primers and 2 headstamp brass
- Completely broke the gun apart and re assembled
- changed scopes
- open barrel channel up more
- different tq specs on action screws

With this all being said I can take 3 3shot groups and one of them will have a terrible group that's normally vertically spread. Im not running the barrel hot and the bad groups will sometimes be on a fresh cold barrel and sometimes not.

Also keep in mind that i have 3 other ultralites that I will shoot in between barrel cooling, off of the same bench with the same bags and I do not get this problem with the other ultralites.

Im thinking either something with the gun/barrel is messed up or that its time to buy a different stock?

Pics attached are 3 groups with 7828 and 3 groups with r23. All variables were the same and as you see i had a bad group with each load
** you gotta decipher through the lines and X marks but there is 3 3shot groups on each pic. The X marked holes where previous shots from another rifle.
What's the velocity and SD between good and bad groups?
 
I hate to say this but for me, Step 1 is ; I would start by checking all screws for correct tightness. Action screws, bases screws, Scope Ring screws, and then shoot 3 three shot groups at 50 yards, and shoot three shot groups at 100 yards to see if that made any difference. I would also check a few my hand loads. Powder Charge, COAL and OGIVE . If all that is just as you wanted and expected it, I would then consider changing out the scope to another one and fire some groups to see if the problem lies in the scope itself. I know it's real simple stuff , but that's how I would START the process.
 
Nobody has mentioned cleaning the crap out of barrel. I had a 'hand me down' 243 that wouldn't shoot any thing consistent. Shoots great now that I have all the copper/carbon removed. Also check for carbon ring in throat.
Yep that's what I would do ! 300 rounds is easily enough for carbon and copper build up effect accuracy. Happens all the time on my bench guns .
 
Tupperware, no pillers. My others are the same without any issues. But doesn't mean thats not the issue with this particular rifle.
What about a 3rd primer. Is your velocity SD in the single digits. Kinda looks like a node issue to me. Could be a stock problem but check others before spending more money.
 
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