Good luck to you and your son this year. I've really been impressed with how well the TTSX shoots and how they break through bones even at longer ranges. Your son can take out the front shoulder if he wants to and feel pretty good about getting to the vitals, if that is the only shot presented.
I've seen them go through lungs, heart, then break the off side shoulder of a good bull at 350 yards from a 180 in 300 Win and break the spine of a big Russian boar limping away at 520 yards with a 150 in 7 RM.
