andrewjoseph
This not that all of an uncommon story with the SST/SW at closer ranges. I am assuming you ment 250 grain SW.
IfI could I would recommend to you to try some Speer Gold Dot 250 grain HP. I shoot Noslers .451/260 grain but they are expensive, and I + plus several other have found the Bonded Gold with managed expansion realy work well. They are the closest thing thiing to Nosler that I have found but a real resaonable price.
I forgot what gun are you shooting? Nevermind you answered the question... I shoot Gold Dot from a Omega also and I am able to load it comfortably with a MMP HPH-24 sabot or regular Harvester, but if your barrel is tight you might need to try a HPH-3p-EZ or a Crush rib...
Here is a pic ofan some expanded GD's that I have collected from a saturateddirt clay water bar. These were shot at a 100 yards into the bank. You can see they expand only so far then the base which remains intact keeps driving the bullet forward.