No experience on game, but they are crazy accurate bullets. I did a bunch of research and what I could find is that they seem to be a pretty hard bullet, made more for 308s and such. I wanted to use them in a BHW American 30 which pushes them to 2600+, and have loaded them but haven't tried them on anything but water jugs. I lined up 7 gallon milk jugs at 100 yards, and it plowed through all 7 and kept on trucking so I took it as not expanding much at that speed and haven't revisited it. Might be great for a tougher hog but was worried they might pencil through a deer if it didn't hit significant bone.
I think Hdy loads the 125 sst in the bo. I load those in the 30 RAR at 2825 and will be trying them out this fall on antelope and deer.