I gave S&W customer service a call yesterday to clarify whether Hoppe's Nitro Solvent was alright for the scandium PD revolvers. I already had the 340PD and just bought and paid for the 386PD. The 386PD is plenty good shooting with 158 grain 357magnum rounds. The gun is light but the recoil is very manageable to my hand. The 340PD ain't fun with the same round but doable.
So S&W said that Break Free would be a better choice for a solvent on the cylinder/chambers while Hoppe's is alright in the barrel. They recommended Never Dull for the face of the cylinder. A brass bore brush with the Break Free is alright as well within the chambers of the cylinder but only the Never Dull on the face of the cylinder.