I ran into the same thing with SST's from Hornady when shooting my Black Diamond XR. They loaded so hard I actually broke my short starter. And one of them I had to.. [&o] pound down the barrel to get it seated so I could fire it off. I was really disappointed that very first day I got to shoot my brand new Black Diamond. I was ready to send it back and swear off inlines.

I then bought some of the Thompson Center Shockwaves, and the difference was like day and night. It is all in the sabot. Get some Harvester Crushed Rib sabots in .452 and those SST's will load like a dream.