You might want to try a formula provided by a poster here that seems to work for lighter bullet weights.

First develop the full bullet weight, full velocity load that matches what your rifle was regulated with.

The find a bullet you would like to try that weighs about 70% of the bullet weight the rifle was regulated with. Load this bullet over the powder charge for your full power/regulation load. See how it shoots and adjust from there.

This formula works pretty well in my rifle.

JPK