it's the LIQUID in the live target that makes
the frangible's act differently. 30 years ago, I was amazed that a 50 gr Hornady "SX" sp would not exit a chuck, but it blew holes in 1 side of a 1000 gal steel tank, and held togeter enough as it traversed 5 ft of air, to make BIG dents, in the far side, very noticible on the outside of the tank. The metal thickness was about 3/16". This was from about 100m away, too.
I dont think much of bullets that are designed to break into dust at impact, but the ones that break into 3-4 relatively large chunks, if made out of solid copper, or tin, at Mach II velocities, (from pistols) those are impressive in their effects.