I tried o rings and screw pressure.
To be honest, this doesn't seem like an accurizing issue. 12 shots and anywhere from a foot high and a foot left, to 16" left, to a foot low.
A couple low between 4 and 8", a couple high and left about 8-10"
One actually hit where I was aiming, and a couple missed the cardboard target altogether.
All at 40 yards.