I have two factory Winchester 300 wsm
rifles that both shoot under moa all the way to 1000 yards. We have access to a range that has 6 metal targets with ar 500 steel at each distance from 300 to 100o yards..
Our pet load in both guns are factory Winchester brass full length sized, fed 215 match primer, Berger 190 v ld at 2.860 coal and 61 grains of IMR 4350.
One gun has a 24" barrel and shoots at 2808 fps.
Other gun has a 26" shillen and shoots at 2800.... Go figure!
I can keep both approx half moa to 1000 yards
Working on another friends this week that will shoot the same load. Will let you know how it goes.
These Winchester guns have long throats and shoot the vld at factory coal of 2.860. They do worse closer to the lands for us.