5.8 gr of Unique if you want to run close to Military ammo I have tested over a Chrony.
As an aside I found 231/HP38 and Titegroup to be more consistent and easier to work with than Unique. 5.4 gr of 231/HP38 or 4 gt of Titegroup worked well under 230 gr plated and lead bullets. 4.1 gr of Bullseye also worked well.
Take Care
Bob