I can probably recover a shot bullet and have a look at the base to see if the Bullseye is burning it up or not...
Someone else advised that hard cast bullets were really not best for regular 38 loads because they probably wouldn't seal.
I doubt the bullet is in the bbl long enough to be burned, it easily could be running out of lube. When I shot the swedged speers the standard load was the bullseye and ppc load of 2.8 to 3.0 gr Bullseye. This gave around 700 fps from a 6" K frame.
Hardcast are not really the best choices for a 38 @ 19-22 BHN. Swedged are closer to a BHN of 8-9, the ideal would be something in the 11-12 BHN class. I think hardcast are a far better choice than a swedged at anythin gother than a book minimum load, though the short bbl may have other effects on powder flame.