This may help, when we used to shoot 10 mts Running Boar (Running Rat!!!) now emasculated to "moving target" by the politically correct brigade, we had the same issue of scopes not being corrected for parallax at 10 mts, generally, other than the mega money ones, they are set up to be parallax free at 100 mts.

The matter was simply solved by obtaining a 0.1 dioptre lens, if you have a friendly lens man, 0.1 is the tolerance on a lens, so a check of "clear plain" lens's often found one at 0.1. It was a simple job to remove the front ring and fit the lens between two "O" rings.

Also be warned that many 10 mt clubs will not allow 12 ft lb rifles due to potential range damage.

But, best of luck in your endeavours to widen interest in target shooting.

Have Fun
Robin