In my opinion, voice lessons might not help you out here. Typically, voice lessons are for improving your tonality, and range, but doing it in a way safe for your voice. This usually isn't what you express in hardcore music. But you may have a great hardcore singer in your area that could give you some tips.

Hardcore singing to me, has always seemed like the singer is straining their voice. That's where you start to get the growling effect. If you can sing a song perfectly, and it is totally in your range it may be harder for you to get the growl. You can get a nice one when you sing a little higher than your range. You get a very big strain, that sounds kind of like a dieing bird if you go way over the top. If you sing low, the growl that you try to produce will end with your voice sounding muffled.

It's up to you. I don't know much on the hardcore category of singing. Ask around in your neighborhood, look up what a few of your favorite singers did or do to sing the way they do.