I'm trying to find out if anyone has used the RCBS 7.62-130-SPL cast bullet in a TC 30 herrett. If so how did it perform, and what were your loads?.

I have used that bullet in other 30 caliber guns but not my Herrett. I would think a good mid-range load and the bullet sized to .309 or .310 would work well in your Herrett.
My RCBS blocks throw very consistent bullets. I cast with wheel weights and water quenched the bullets and they seemed to be accurate in the guns I used.

Lee mold, tho.