Last few lots of Nosler ammo I shot through my 308 was terrible, 1.5-2" "groups" (more like shotgun pattern, gun shoots fed gold medal ~.75"), pretty inconstant velocity and some erratic pressure signs on the brass. This was all bought pre-panic back in 2019 or so.
I'm not sure why everyone seems to think this is a rifle issue
Ejector marks with lack of flattened primers on a new gun makes me think the chamber might have just a slight amount of oil/solvent in it, especially if you cleaned it before the first shots.
ETA: as others have suggested, get a headspace comparator and measure the unfired ammo, I'd also measure the headspace on the fired cases and compare to the unfired cases that wouldn't chamber and see if they are longer or not.