I was wondering, I know that some of you guys have done alot of hp testing. Do pentas open at a lower velocity than a large hp? Do they expand more? What are the advantages and disadvantages of each? Any ideas? I just got an mp-mold with a set of penta pins, and plan on loading them in 9mm and .38spl. The 9mm will be run at a higher velocity. Thanks in advance for any insight anyone has on this subject.