Well this one is a little odd for developing a load. Group @ 200 meters is just over 2" perfectly vertical. Zero variance left to right. Usually get the triangular or stringing which is easier to dissect.

100 meter is almost 3/4" ragged hole vertical. But 400 meters is about a 10" group

Bullet stabilizer software shows that bullet stabilized very well over 3800fps. Chrony has the 38.1 charge with WLR primers at 3985-3990

Odd is that a 5 shot group is not walking up on heat. 1 can be center, 2 can be high, 3 low, 4 low, and 5 center or high. I varies, but point is a 5 shot group isn't stringing up and out from heat.

22-250 1:9 twist

current test load -V-max 60gr - H380 @38.1gr. WLR primer Seating is .005 off the lands

Did all the standard ladder testing - seating .005 to .080, Fed and CCI primers (both open the groups up) and changed charge from 36.5 up to 38.5.

I've never had a 22-250 that was picky on brass. But isolated that, and no change.

Any thoughts

Your way over my head in the technical aspects of this^^^

I have had this in various rifles myself. Usually it boils down to a bedding problem. Or just a bad barrel.

Check torque settings on the action screws. They might need to be the same or could need to be slightly different front to back. I guess this would be related to bedding?

is barrel clean? how is the crown? barrel floated? action bedded? have you tried other bullets?

I would try a different bullet with a higher BC.

What does the higher bc do for accuracy

Erratic unexplained bullet consistency in my experience is usually a loose screw somewhere. Scope base or gun. It really takes very little wiggle/ movement within the mechanical system at longer distances to equate to groupings like you are experiencing. Could even be the reticle within the scope, but that is probably less likely if it is a quality piece of glass unless you have had a hard knock on the scope lately.

What is the rifle in question first off ?

I had an X bolt 22-250 9 twist that wouldn't group anything over 60 gr.
Sold it at a gun show.

Since it's a vertical string I would bed the lug and check all bolts for proper torque. And then go back to the bench.

And though I've never had an issue with a v max making fine groups,I would try a different bullet. Your rifle just may not like them.

Begara rifle

Doesn't like anything under the 60gr. considering trying something in the 64ish gr bullet. I get a target speed to work up to using the Berger stabilizer software. Its been spot on for the last 15-20 rifles I worked with.

Begara has a spec of 55inch pounds for the action screws. They were both right there. I bumped them up to 58 inch pounds and just shot. Identical results

Yeah could definitely just be the vmaxes.. can't tell you how many guys have told me they went from Vmaxes to somthing like a Berger because the vmaxes just fell apart, group wise , at longer distances

That 1:9 could also be right on the tail end of what it needs to stabilize those bullets at this distances

hi BC bullets fly better at extended range