In my 22 cf adventures I've tried a lot of Savage barrels with jacketed bullets with loads at or just under starting. As far as I can recall, no barrel in any caliber failed to shoot these loads ~ 1", this for just a few groups.
Shooting 22 cf jacketed loads at cast bullet velocities, it sorta seems that the barrels that don't shoot jacketed accurately don't shoot cast accurately.
I haven't got enough data to be sure, but...
So, with a new gun/barrel-rifle caliber, try a few groups with a known-accurate cast load and jacketed bullets. If it won't shoot ~ 1” 5 shot 100 yard groups, it may not shoot cast bullets accurately.
I mentioned this to John Alexander, who has something to add.
joe b.