jparker29,You don't need a bigger gun and the best bullet for your rifle is the one that is the most accurate.
I have killed elk with the Noslers,Accubonds and yes.......Even Corlocts.There are some very good choices out there today.....Partitions,Accubonds,Fail Safes,Triple Shock and others.Choose any of these. Find which one is the most accurate and most available and use that one.I would use the heaviest grain availablefor yourcaliber as well.
I currently shoot the Accubonds out of my .300wsm. Super accurate!!!!
Glob