I don't have both powders so I can't give a good answer to the OP's question, but I have used CFE for Pistol in several 9mm loads. I haven't used nor will I guess at the performance of HS-6. CFE meters well, and at my levels, mid range, it burns clean. I have used it under cast/PVCed 125 gr bullets, 124 gr Gold Dots, and 124 gr. RMR FMJFP and JHPs. I have a brand new Masada that I'm waiting to shoot so I cannot attest how the powder performs in a 4" bbl, but I've seen no downside when used in my Ruger LC9s Pro...