I agree with most of you on the fact it's fit rather than hardness. However you have to understand that relationship if you have to fine tune a situation. I got a hold of a bullet maker and he helped me understand that fit is the most important of the two. He often has customers that want a harder bullet than what they have to fox leading problems. Ofter it's a mix of sizing correctness and powder burn rate. Never considered any of this prior to this thread.

So with all of the knowledge I have acquired as a result of asking a very stupid question, as I look back.

I am going to load the Hunters Supply 158 gr hard cast lead bullets in my 38 spl and 357 mags. I think that fit is far more important than hardness. I can send them on their way in the 38 spl at around 850'/sec and the 357 mag at 1150'/sec. and they will do a good job. Look for leading and adjust.

I am not going to load the Speer GD 158 gr in the 38 spl. If I want to use a jacketed HP I will drop down to a 140 to 125 grain bullet for ensured expansion. I will use the 158 gr Gold Dots in the 357 mag.

I have been investigating the burn rates of different powders. Something I never thought of before. I always just looked at the recipes in the cook book and went for it. After analyzing the burn rates I am starting to understand how one can control some of the variables in hand loading. I seems that most of the requirements of powders for the 9mm,38 spl,357 mag, 45 auto run in the top 1/4 of the fast burn rates. So if you have a short barrel vs a long barrel you might look for a faster burninn rate in the powder. I always went with what I had on hand & didn't understand the needs of the pistol & projectile I was using.
So now I am starting to appreciate the art of "Hand Loading" when understanding how to control & change the undesirable results.

Well I have a lot to digest and I really want to thank everyone for their help.