Especially the heavy-for-caliber loads. I've never been a fan of the heavier rounds, instead preferring a little speed; not quite a "speed freak" (like 135gr .40 loads, or 115gr 9mm) but some juice nonetheless---155gr .40's, 124gr +P 9mm's, 185gr +P .45's. Over the years I have tested many different bullets, all with the same protocol I've mentioned here before: through 4 layers of a towel and into my swimming pool. Now I know water enhances expansion, but IIRC it is closer to gelatin results in that category than penetration measurements. They all rest on the bottom of the pool afterwards so it's impossible to tell when they came to a stop and gravity took over. With expansion being *similar* to gelatin I tend to look at how a bullet acts once penetrating the "clothing". Especially with the JHP's of years past, clothing would trip them up significantly and hinder expansion. This was exagerrated in heavy loads for caliber, and led to my "need for speed". Maybe someday I'll buy a side of beef and let 'er rip! Enter the modern era of handgun bullet design. Federal HST has really impressed me. While the "lighter" loads open up fine, the heavier ones in each caliber really shine, and this from relatively short barrels no less (Glock 36, Kahr CW9). I notice the skives cut into the jacket are longer on the heavier loads, no doubt aiding expansion at the lower velocities that heavier loads produce. For the first time I will load 147gr rounds in my Glock 19 and 230gr +P rounds in my Glock 36. Just gotta find some 180gr HST's out there somewhere for my new Sig P250 (if the other calibers are any example the .40 cal 180gr'ers should exceed the lighter .40 HST's in expansion).