Fx hybrid slugs 22gr. 22cal

Wondering if anyone has groundhog experience with these. I normally shoot jsb 18.13 .22 out of my avenger that’s tuned to 34fpe. I bought the bullpup2 and tuned it for the fx hybrids to 33fpe. Thing is a laser by the way with the slugs out to 80 yards for me so far.

Anyway I just went for a ground hog and had perfect shot placement around 35 yards and had to take follow ups, up close. Do these not penetrate the skull? Just got a ground hog with my notos at 30 yards and it dropped solid with the jsb 18.13s which is only putting down like 23 fpe…

Any help would be appreciated. Thanks guys!