I've read of some people getting very good results from the very light loads using pistol primers instead of rifle. With regular loads that would be a big "NO!", but with these pressures are very low. So, it needed trying. All used 3.2 grains of Bullseye propellant, bullets seated to the same overall length as the previously-tried loads.
First in .303, with 160-grain spitzer
7.62x54r, with semi-wadcutter,
.30-06 with 115-grain spitzer
Indications are that all three rifles prefer the pistol primers with the wadcutter bullet; the others it's a toss-up. One more variable: some stuff actually shot better in the .30-06 using a lighter charge, 3.0 of Bullseye, so ought to try that with the pistol primers as well.
At this point testing is really just tweaking things a bit to see if any improvement. Both Unique and Bullseye make good light target/varmint loads with these light bullets. And a little bit more propellant with a heavier bullet can be quite accurate with some rifles/bullets while giving more oomph on the target end.
This stuff is fun.