I tried wads, fillers etc, but never had great luck with them, and certainly not enough to go trough the trouble.
When shooting my .38 Spl at 300 yards I had to raise the barrel and then lower it slowly to level to get more consistent shots.
When I started testing powders back against the primer vs forward against the bullet it became very apparent why. Some
powders are worse than others. Later I started testing powder level as well. Some powders like that, and do just as well as PB,
even better sometimes.
I learned which powders did well (Not losing a lot of velocity) powder forward, and chose powders that could also give me accuracy to go with it.
These targets were shot with .38 Spl Load # 82 & Load # 107. 18 shots each, 6 powder back, 6 powder forward, and 6 powder level. At least up close accuracy was good and to the same point of impact, and the PBF & PL numbers were good compared to the PB numbers.
The original test of #82 was in 2011 @ 90ish degrees for an average 739 powder back and 741 powder forward.
The original test of #107 was 2013 at 74 degrees for an average 787 powder back and 788 powder forward.
That day of the target #107 was 815 PB, 790 PF, & 809 PL @ 47 degrees.
These are outstanding PB & PL numbers by the way.