With my springer pistols Ive discovered that artillery hold is NOT most accurate.
I use a firm hold with all for best results.
They are very hold sensitive, every pistol likes a slightly different grip.
One like squeeze with shooting hand, the other with non-shooting hand.
One likes a straight thumb, other a bent..
trial and error really
But Ive managed 1cm edge-edge groups of 5 shots at about 5m so accurate it sure is.