I've been loading 70 grain TSX ammo on and off for years and a friend is asking if I can load the round with less powder for a quieter/less powerful round to shoot a groundhog without alerting the whole neighborhood. Going to be a high elevation "perch" so little concern about the round carrying onto another property. Is there a round that already fits this bill (a subsonic round anyone has used) or is lowering the "dosage" on my handloads a way to go?