Thread: Reloading and sonic crack questions

So to say I know sweet stuff all about either would be overstating it.

First question, I know that a bullet going super sonic creates a crack, does the faster the bullets going or the larger it is make it a bigger bang?

Secondly, could I for instance take a factory 7.62x39 round, rip the existing projectile out an ram a heavier one in? and if so what gear would I need to do it? or is it one of those jobs you need the full kit and start from scratch?

Cheers