For years, I had the mindset that you want the bullet to achieve enough velocity to reliably expand - even if that meant going to a lighter bullet.
That was then. This is now.
After reading a lot of stuff on TFL from people who are clearly knowledgable, I have adjusted my mindset. To stop a BG, you need to make a hole first (or two - entry/exit). Expansion is secondary.
My HD gun is a .357 Magnum. I switched from 125g HP's to 158's.
But above all, shot placement is king. A well-placed wadcutter will wreck a BG's day.
Gun control laws benefit only criminals and politicians - but then, I repeat myself.