It's been my understanding that Ruger heat treats the 38s and 357s cylinders to the same level. What I would worry about would be over pressure in the 38 case due to compacting the powder charge. A 357 level load of Unique in a 38 case with a heavy jacketed bullet could be disasterous. But 38/44 level loads would be great. Then to separate those loads from 38 J frame Airweights.
I use a nickel case for 38/44 loads and a brass case for standard 38s. Immediate recognition of power levels.