I think those Hammer's are solid copper bullet's? I also think the tip's are scored so they will expand at impact. What that means to me is they will hit at pretty much any velocity you could drive them from a rifle cartridge and penetrate about as good as your likely to need and get the job done. I use cup and core bullet's, just can't bring myself to use the more expensive bullet's, not that much income! But tell you something about those monolithic bullet's, hit a deer or what ever with a bad shot and it's still a bad shot and a wounded animal! You want to make sure a bad shot works, use a 20mm canon!