Oddly enough Penal are quite good at long range fight once vetted. Their vet 1 ability and accuracy buffs make the quite good at prolonged cover to cover fights.
~20 DPS spread across whole squad.
Grens alone have 13,5 of focus fire DPS and additional 10 from regular Kars.
Penal vet1 is not useless, but its also not outcome changing, instead of losing 16,6% DPS per model loss, they lose ~13%. It helps, but its not going to overpower anything.
Penals can fight at long range, but saying they are good at long range at vet compared to any other squad capable of long range fighting, including bar rifles is covering the truth at the very least.