Gryphon,
I tried different loads of IMR4350 & AR2209 & variations of length for years without success in my .308Norma Magnum (Federal 215 primers & 180gn Hornardys). The Norma Factory loads were consistently about an inch for 3 shots at 100 yards - my loads at least double that! Had an old benchrest guy that regularly did the "Fly" event at 500m, walked past & shook his head! Asked me what powder I used & he just said "try 2213sc", then walked away - so I did!
Groups shrank overnight!
Now it can shoot (If I can hold steady enough) just under MOA with both Hornady 178gn A-Max & 180gn SPBT & to the same POI.
My only problem with the rifle is that it is a bad fouler - it takes a lot to clean!
Try slower if 2209 doesn't work
Cheers
93x64mm