I have been using CCI #550 magnum primers in my .38 loads and find they work very well with HS6 with both 125XTPS and 158XTPs. Have not quite worked up to +P loads with them yet, but they seem quite manageable. I also have 5k of #500 small pistol primers, so I am sure that I will load up a hundred or so and see just how much, if any, difference the two primers show...

Don't really expect much difference from what I have read, but who knows...