I picked up an older 1st Gen action with the solid bottom reciever, 4.52" screw spacing, with a .378 bolt head. Plan was to swap out to a .473 head but it seems there is a few small items that keep it from being a drop in. SO for those of you who know these, is it easier to cut the notch into the new bolt head or easier to take the dimple out of the bolt? Or do you know where I can find a drop in .473 head for this? Thanks