Welcome to the forum barman!
Thunderheads should fly well so check out your set up. Are you using a cocking mechanism? Do your broadheads spin true?
Don't be afraid of the Wasp Jackhammer. If you are spitting the arrow out near or past 300 ft/sec then you need a broadhead that flys well at high speed. Try some non expanding heads like Slick Tricks well as Magnus Stingers, G5 Striker, Razorcaps and more. The Jackhammers have to be double banded if its going near or more than 300 ft/sec. I think i will experiment with this one next. http://www.fusearchery.com/broadheads/kumasi.tpl