I make it bounce sometimes too.
It's because I'm dropping the ball too early. Might be the thumb hole that isn't quite right for me atm.
But I was worse a few months ago, since I dropped the ball on the uhm part of the floor you're walking on (the translates wouldn't translate the word we use for it in norwegian
). I used to drop it like 2-3 feet before the foul line. Now I go to where I used to stand, and then take one big step forward. I take small steps.
Now I'm on the correct side of the foul line.
But that doesn't mean I don't drop it too early still. I try to drop it later, but you aren't supposed to clench the ball, which I have to do.
The PSO will be giving me a new grip on the balls I'll buy from him next month. He'll drill the thumb hole at an angle, more than in the balls I already have. That should help me not drop too early.
Do you bend your knee when you throw?
If not, try doing so.
And if you feel like your thumb goes out too early (besides your leg for example, like me), then go to your PSO and have him watch you bowl. MAybe he'll give you a new grip too, if he's good at his job.
Also, don't look down when you throw, look up, be straight in the back, bend knees. Don't be stiff as a board.
A guy who'll be joining the club I'm in used a weight thing to train his knee bending and such.
He pretended to be throwing a ball, swung the weight and bent his knee.
Eventually he became so silent when he throws the strike throw. There's almost no sound when he throws now