Are the guard screws tight holding the action to the stock? In particular the front screw?
If they were try shooting with the rear guard loose a half turn. If that works it needs bedding.
What do the fired primers look like? Are they the same?
What does the fired brass look like? Soot on the brass?
I just shot a 243 last Wednesday with a good load at 100 yds and it made a 2" vertical group.
I found the front guard screw to be a little loose. After tightening it made a 1/2" group at 200 yds.
Of course it can be more complicated like a guard screw that bottoms out on its end etc.
