shooting a 6mmAI 87grn Vmax H4831sc, I've done a lot of reloading and never seen a gun do this, shot a one hole group at 100 yards, within 15 minutes loaded 3 more same with brass of the same lot and it shot a 1/2" group, this gun has done this on two different occasions. Does it not like the powder, bad bedding? This is a custom rifle. Anyone else have this happen and find out why?