Went to the range today to test some more loads in my new .416 Remington Magnum. I was firing 400 grain Hornady DGS over top of 79.0 grains IMR-4064. Velocity averaged 2430 fps with an extreme spread of 35 fps. All shots were off sandbags at 100 yards.

What's puzzling me is the grouping I got firing 7 rounds total. I fired a 2 shot group, let the barrel cool, fired 3 shots, cool, fired 2 more shots. The first 2 shots were all but touching at 7 0'clock on the bullseye. The next 3 shots formed a loose clover leaf about 2 inches directly below the first shots. The final pair of shots almost touched each other but were 2 inches below the second group.

So overall the 7 shots formed a 4" group that was vertically oriented in 3 distinct sub-groups.

Any suggestions on what my next steps should be? Forget this powder bullet combo and move on, try a little more/less powder, try a different bullet, or is it likely my shooting was off today and I should try again tomorrow?

Any suggestions would be appreciated.

Vertical dispersion often suggests improperly tightened action screws. That would be my first place to check. If your gun is new and you didn't tighten your action screws both before firing and again after the first few shots, then that potential cause is highly suspect.

Perhaps something is settling in for the rifle. Also check your action screws.
You have an accurate rifle with on tiny little gremlin.

how is your rifle bedded? always check the screws on bigger bores,, this is a lead cause of split stocks.. is it scoped? the the rings move, or settling on the bases?