A PRB follow up

[3seasons]

One month or so ago I was wondering here about hollow point round balls. I now have the photo.

Granted, this is unscientific at best but: near my target is an old spring house, the poured concrete foundation is 10" thick, so the corners are fairly massive.
Just for kicks, I will sometimes fire into the corner; that is what I did for the rounds in the photo at 80 yds,75 gr 777. The powerbelt was in my box, unsure of the grains but belt was green; PRB .490 swaged.

Now,both rounds struck w/in inches of one another BUT while the round ball hit & dropped w/in an inch of the concrete the powerbelt I found 10 yds even in front of the target.

I know very little to nothing about ballistic co-efficients,etc but imagine that these "results" indicate that while the powerbelt has more energy upon impact, the round ball released all it's energy while the 'belt did not. Or maybe not. This was the reason for my inquiry of hollow-point balls-I am curious what this photo illustrates.

[cayugad]

It looks like both of them splattered pretty good, hitting that concrete. The heavier the projectile will have more energy. So a .50 caliber roundball is 177 grains while a green band powerbelt is I believe 295 grains. Much heavier. So of course the powerbelt would have had more energy with the same powder charge. Why one splatters and falls to the ground while another bounces, could be where they hit on the concrete, the shape of the projectile, and a hundred other things.. I just don't know.