Here is a link to several bullets shot at smokeless speed and T7 speed into perma gel.

http://www.modernmuzzleloader.com/forum/viewtopic.php?f=14&t=6450

The lowly 250gr XTP did surprisingly well although i would still recommend being careful of shot placement.

You didnt mention your powder load with the SST or which weight. Some of the older SSTs had a harder tip material and for some reason did not expand as easily with mild loads.