What's going on ?

I have one hole groups at 100 yards and 5" patterns at 200.
Model 12 in 22-250 Rem.
52 gr SMK.
Vihtavuori N135 powder.
33.1 gr.
BR2 CCI primers.
Winchester brass.
I have messed with all the suspects.
Changed stocks, floated the barrel and the tang.
Scope is tested and tight.
Parallax is correct.
Crown is fine and bore looks good.
Different shooters.
Different seating depths.
1-12 factory twist barrel.
EVERYTHING I try gives roughly the same result.
Do I need lighter bullets to stabilize at longer ranges ?

To me?.....a heavier projectile may be the cure.

Try the 69gr match kings and some reloader 17.

Could be your rifle just doesn't like this particular combo you are trying. Change bullets and powder and see what happens.

I hope I can help.... I've been shooting 22 cfs for decades in both factory chambers and wildcats. Yep, I've found some combos that a certain rifle just didn't like, while a different gun loved 'em.

If you want to stick with this weight bullet, and I assume you are using Sierra #1410 52 gr HPBT?
Try the Sierra 53 gr HP. This is a flat based bullet.
Stepping up a bit in weight, try Nosler 55 gr Spitzer BT. I've always found that both HP and plastic tipped bullets shoot better for me. I 'feel' that the center of mass being more to the rear helps the bullet stabilize more.

Maybe off topic, but I have a Colt HBAR AR-15 with a 1:7 twist bbl. I was always satisfied with the light pills UNTIL I tried bullets in the 69-75 gr range. 'Almost' turned it into a bench rifle... ha ha

ron