Update: My best so far has been 55.5 H4831 w 135 Bergers. I’ve tried various other combinations of H1000, N565, N555 w Berger 144, 153 Atip and 147 ELDM.Have you found 143 ELDX to work better for you than other bullets? I tried some Hornady factory loads. Precision Hunter I think. one 5 shot group was the best I’ve shot with this rifle - 0.550, but then shot another 5 shot group that was 1.20”. Still might buy some 143 ELDX to try.
MY rifle is short action, 2.990” mags, has a Bartlein/Snowy Mtn Rifle bbl, 22”, 1:8” twist.