Questions about the process

[Harvey_NW]

23-23.5 gr H4895, N140.
23.0 gr 8028 XBR
24.0 gr varget

This is in larger capacity brass like ADI, LC, Lapua. Might be smaller charges in something like starline.

If none of those shoot, give up on that gun.

That is a great start BUT
I have found that the 223 generally is fussy with charges on the lower end of the spectrum using the heavier bullets.
I think those charges are all about half a grain low for best results.

I have used all those powders with 77s.
I would rule out Varget unless you have a chamber with a long throat and a magazine to match because it gets really crunchy.
8208 and 4895 are both great, however 8208 meters much better and is first choice for me, particularly through a progressive.

@DeepMauka