On a more serious note...
I have the exact same rifle...even the color. I shot an AI AT for a few years before buying it. Shot 308 and 6.5 Creedmoor cartridges. I was pretty good. Could hit 4" gongs at 500 yards most of the time.
I bought the AXMC in 338 LM and the first 5 times I shot it, my groups at 100 yards were TERRIBLE. Not as bad as the OPs but in comparison to the groups out of my AT, they sucked. After the third time, I actually brought the AT with me and shot it. Shot it well. I bought this rifle from another member here. It was unfired. All I could think was HOLY SHIT....I got a lemon.
I posted a similar thread here and was given the same advice that
@THEIS suggested. I really did not appreciate being told I was probably flinching. Well I had my wife video me. I was prone and she sat on the top of an adjacent bench and videoed me shooting it.....I was flinching. Sometimes I was slapping the trigger and sometimes I would move just enough to allow the butt to move which gave me the vertical stringing that I see with your groups. The issue was that my flinch manifested itself into different errors that made the groups appear very bad. It would have been easier to diagnose if my method of flinching was due to making the same error repetitively. In my case there were a few errors that the flinch would cause and they were random.
After I FOCUSED and shot the rifle a few times, I solved the issue and can now shoot it as well if not better than the AT.
Moral---it generally is an absence of fundamentals
YMMV