Q: I keep cutting halfshaft boots on the car. What is causing this?

A: Overheating the CV joint will inflate the boot on the halfshaft.
 This happened to me only on the driver's outside boot road racing the car.
Venting the boot will prevent that.
Take a straw from a WD-40 can and slip it under the little gap on a worm screw clamp.
That will vent the boot and prevent it from inflating.
Centrifical force will keep the grease inside and it will not leak from this vent.